JP3939664B2 - Purification method and system for lakes and the like - Google Patents

Purification method and system for lakes and the like Download PDF

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JP3939664B2
JP3939664B2 JP2003052413A JP2003052413A JP3939664B2 JP 3939664 B2 JP3939664 B2 JP 3939664B2 JP 2003052413 A JP2003052413 A JP 2003052413A JP 2003052413 A JP2003052413 A JP 2003052413A JP 3939664 B2 JP3939664 B2 JP 3939664B2
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water
purification
treated
lakes
region
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JP2004261661A (en
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裕明 依田
聡 湯本
穣 森田
典英 佐保
文隆 田中
潔司 十河
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Obayashi Corp
Hitachi Plant Technologies Ltd
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Obayashi Corp
Hitachi Plant Technologies Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00Technologies for wastewater treatment
    • Y02W10/30Wastewater or sewage treatment systems using renewable energies
    • Y02W10/37Wastewater or sewage treatment systems using renewable energies using solar energy

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  • Water Treatment By Electricity Or Magnetism (AREA)

Description

【0001】
【発明の属する技術分野】
本発明は、湖沼などの浄化方法及びその浄化システムに係り、富栄養化した湖沼、ダム湖、港湾などの閉鎖性水域の浄化技術、特に水道水源用閉鎖性水域または観光用景観、リクリエーション用親水性水域の浄化技術に関するものである。
【0002】
【従来の技術】
近年、上水道用水源である湖沼などの閉鎖性水域において、窒素やリン等の富栄養化を招く物質の流入量が多くなり、藻類が大量発生して水質が悪化する富栄養化現象が進んでいる。そこで、水道水の水源または親水性水域としての湖沼、ダム湖等の閉鎖性水域において、富栄養化が進むことを抑制してその水域を浄化するための各種技術を使用した浄化設備が増強されてきた。
【0003】
このような閉鎖性水域の浄化技術は、数々のものが提案されているが、これらを分類すると汚染物質を機械的に除去する技術、微生物を活性化させることにより処理する技術、薬品等により化学的に処理する技術、閉鎖性水域の一部の水を循環させることにより処理する技術等になる。
【0004】
従来技術の一つとして、例えば、特許文献1に開示された水処理方法及び装置がある。この特許文献1には、閉鎖性水域の富栄養化に対する水処理方法及び装置であって、富栄養化に伴って発生する藻類を除去する処理工程及び処理装置と、嫌気性微生物による処理を施す処理工程及び処理装置と、好気性微生物による処理を施す処理工程及び処理装置と、化学的処理により残存するリン分を除去する処理工程及び処理装置とを備えた水処理方法及び装置が記載されている。
【0005】
また、他の従来技術として、特許文献2に開示された汚濁水の浄化装置がある。この特許文献2には、双胴型の台船の内側水面に、上部が開口した凹状断面の桶の複数個を適当な間隔をあけて並設したフロート付き気泡回収用いかだを、各桶の側端部がわずかに水面上にある喫水状態に調節可能に連結するとともに、その気泡回収用いかだの水中下方から気泡を発生させる気泡製造装置を配設し、さらに各桶内に進入した気泡の回収手段を設け、主な湖沼や海などの閉鎖性水域の水中の懸濁物質を除去して、その水域の水質浄化をはかるために使用する汚濁水の浄化装置が記載されている。
【0006】
さらに、他の従来技術として、特許文献3に開示された池水浄化設備がある。この従来技術には、貯水池、かんがい用溜池等における池水浄化設備であって、池の一側部にストレーナおよび浄水装置を配設すると共に、他側に礫、砂等の敷設された親水ゾーンを区画形成し、浄水装置で浄化された池水を導管により人口滝を経て親水ゾーンに導くようにし、親水ゾーン側ストレーナに向かって水流を生起させる水流発生機を適所に配置した池水浄化設備が記載されている。
【0007】
【特許文献1】
特開平2−95498号公報
【特許文献2】
特開平5−287号公報
【特許文献3】
特開平4−90898号公報
【0008】
【発明が解決しようとする課題】
しかし、閉鎖性水域の富栄養化を促進するリン、窒素などの物質は主として、その閉鎖性水域に流入する河川から供給されている。これらの物質を含む河川水は閉鎖性水域に流入して、そこでの滞留水に希釈されるため、従来の浄化方法および装置では大量の水(閉鎖性水域全体の水)を処理しなければならなかった。これによって上記従来技術では、浄化設備の製作コスト、設置スペース、駆動エネルギーなどが大きくなってしまうという課題があった。
【0009】
本発明の目的は、設備コスト、設置スペースおよび駆動エネルギーの最小化を図りつつ、湖沼などの浄化領域でのリンや窒素などの汚染物質による富栄養化を抑制することができる湖沼などの浄化方法及びその浄化システムを提供することにある。
【0010】
また、本発明の他の目的は、比較的貯留水量の大きな閉鎖性水域の水質改善をより効果的にまた確実に遂行することができる湖沼などの浄化方法及びその浄化システムを提供することにある。
【0011】
【課題を解決するための手段】
前記目的を達成するために、本発明の湖沼などの浄化方法は、湖沼などの閉鎖性水域に河川などから流入する水の一部を取水し、この水を物理化学的に処理して主にリンを除去する第一の浄化工程と、前記閉鎖性水域を深さ方向に仕切って形成した浄化領域に前記第一の浄化工程で処理された処理水を導入し、この処理水を前記浄化領域内で生物処理して主に窒素を除去する第二の浄化工程とからなる。
【0012】
前記他の目的を達成するために、本発明湖沼などの浄化方法は、湖沼などの閉鎖性水域に河川などから流入する水の一部を取水し、この水を超電導式磁気分離処理して主にリンを除去する第一の浄化工程と、前記閉鎖性水域を深さ方向に仕切って形成した第一の浄化領域および第二の浄化領域に前記第一の浄化工程で処理された処理水を分流してそれぞれに導入し、前記第二の浄化領域に導入した処理水をその浄化領域内で生物処理して主に窒素を除去する第二の浄化工程とからなる。
【0013】
なお、本発明のその他の手段は以下の記述から明らかにされる。
【0014】
【発明の実施の形態】
以下、本発明の一実施例の湖沼などの浄化方法及びその浄化システムを、図1から図7を参照しながら説明する。
【0015】
図1は富栄養化湖沼に流入する河川を含む浄化対象湖沼を上空から見たところの俯瞰図である。
【0016】
湖沼、ダム湖、港湾などの閉鎖性水域2においては、リン、窒素などの富栄養物質を含む生活排水や雨水が流入河川1を通じて多量に流入する。適当な流入負荷対策をとらなければ、閉鎖性水域2内に流入する富栄養物質は、閉鎖性水域2内に滞留した後、その一部が流出河川4から流出するが、多くが閉鎖性水域2内に蓄積される。流出河川4の閉鎖性水域2に近い部分に越流せき4aが設けられている。
【0017】
これによって、閉鎖性水域2内の水の富栄養化が進行し、藻類が大量発生し、水質悪化や透明度を低下させて景観が損なわれることになる。また、係る富栄養化は生態系にも著しい変化を与えることになる。即ち、その閉鎖性水域2に生育する水生植物や昆虫類、さらにはそれらに依存する魚類や哺乳動物などの固体数の減少や絶滅を招くおそれがある。また、係る閉鎖性水域2を水源とする利水において、水道の水源などに用いる場合には、浄水供給設備の負荷増加や供給水質の低下(例えばカビ臭など)を招くことになる。
【0018】
そこで、係る閉鎖性水域2の富栄養化を防止するためには、閉鎖性水域2に流入する河川水に含まれる富栄養物質のリン及び窒素成分や浮遊固形物などを分離除去する必要がある。しかし、一般には、河川からの流入水量は季節によって大きく変動するために、常に流入水量の全量を浄化することは経済性の観点から難しい。また、リンと窒素では浄化方法が異なる。特に窒素は生物の吸収作用を利用する必要があり、生物の吸収作用の他に物理化学的な除去も可能なリンに比べて、高速除去が難しい特徴がある。
【0019】
このようなことから、効率的な浄化方法および浄化システムの設計にあたって、浄化水量、リンおよび窒素の除去率の要素をどのように設定すれば、建設コストやランニングコストを最小にして浄化効果を最大限にできるかを検討した。
【0020】
その結果、次のことが特に有効なことがわかった。主として水道や農業用水の水源として閉鎖性水域2を利用する場合、使用水量に見合った水量を浄化する。そして、富栄養物質濃度の高い状態の水(即ち、流入河川1の水あるいは流入河川1から閉鎖性水域2に流入した直後の水)を取水浄化する。浄化方法として、一番目に物理化学的な方法によって高速浄化が可能なリンや浮遊固形物を除去し、次いで生物処理によって窒素を除去する。窒素除去は閉鎖性水域2内に浄化領域を設けて、植物の生育や閉鎖性水域2が本来有する自然浄化能力を発揮できる環境を準備する。
【0021】
さらに具体的に説明すると、本実施例においては、富栄養物質の最も濃度の高い流入河川1の河口部付近に河川水取水口1aを設置してこの河川水取水口1aから必要水量を取水し、物理化学的処理設備を構成する超電導式磁気分離装置5を通して主にリンや浮遊固形物を浄化処理する。この処理の詳細については後述する。
【0022】
超電導式磁気分離装置5で処理された処理水は、第一処理水放出口5aを通して、閉鎖性水域2内を第一の仕切り体10で仕切って形成された浄化領域6に放出貯留される。なお、第一処理水放出口5aは浄化領域6に対して言えば処理水の取水口を構成することになる。浄化領域6は、浄化領域6内を第二の仕切り体14で仕切って形成された複数の浄化領域6a、6b(本実施例では、第一の浄化領域6aと第二の浄水領域6b)により構成されている。
【0023】
第二の浄水領域6bは、湖岸3に沿って流入河川1側から流出河川4側に長く延びるように設けられている。第一の浄化領域6aは第二の浄化領域6bに隣接してこれを取り囲むように設けられている。したがって、第一の浄水領域6aは第二の浄水領域6bを介して湖岸3に沿って長く延びている。第一処理水放出口5aは複数に分岐され、複数の浄化領域6a、6bに処理水を分流して放出するようになっている。第一処理水放出口5aは第一の浄水領域6aおよび第二の浄水領域6bの流入河川1側の端部付近に位置するように設置されている。
【0024】
利水取水口9は浄化領域6内の反取水口側に設置され、浄化領域6の処理水を水道水や農業用水などの水源として利用できるようになっている。本実施例では、利水取水口9は第一の浄水領域6aの反取水口側の端部付近に設置され、第一の浄水領域6aおよび第二の浄水領域6bの両方を含む処理水を水源として利用できるようになっている。
【0025】
図2に示すように第二の浄水領域6b内には植生7が植えられている。この植生7には閉鎖性水域2内に既存する植物も含まれる。第二の仕切り体14と植生7とにより生物処理設備30が構成され、第二の浄水領域6bに流入される処理水に含まれる主に窒素が除去される。この浄化された処理水は第一の浄水領域6a内に流出され、さらには利水取水口9から利用水として取出される。
【0026】
このようにして、超電導式磁気分離装置5による物理化学的処理工程および植生7による生物処理工程により、流入河川1の水中に含まれるリン及び窒素を順次除去するので、効率的に富栄養物質を除去できる。そして、従来のように富栄養物質を含む河川水が流入した閉鎖性水域2全体を浄化してそれを取水利用しなくてよいばかりでなく、第二の浄水領域6bにおいては本来有する自然が復元される可能性が高まり、親水性も一段と高めることができる。
【0027】
このような浄化システム構成にすれば、少なくとも、浄化領域6から取水利用する水の水質低下も防ぐことができる。さらには、植生浄化設備においては、第二の浄水領域6bの水質の改善によって、従来閉鎖性水域2内に生息している水生植物の生育が促進されて、ひいては、本来の第二の浄水領域6bが有する生態系の部分的な回復が図られ、水質がさらに改善されるという一連の自然の持つ浄化メカニズムが復活される。したがって、浄化領域6全体としても富栄養化の進行が食い止められ、利水、親水エリアなどとしての有用な水域に改善することも可能になる。
【0028】
ここで、雨季や洪水時などに河川水量が増大しても、超電導式磁気分離装置5によって取水処理された水は仕切り体10によって閉鎖性水域2の他の領域からほぼ隔離された浄化領域6に貯留されるので、浄化区域6内を浄化された水域として確保できる利点がある。
【0029】
図2に示す植生7は、第二の浄水領域6bが遠浅の場合に採用されるものであり、水深の浅い領域の土壌に葦などの植物を直接植えることによって構成されている。図2に示す第二の仕切り体14は、水深の浅い領域の底から立ち上がって第二の浄水領域6bを形成するようにしている。
【0030】
また、水深が深くて、水生植物を土壌に直接植えることが困難な場合には、図3に示すように、フロート12を取付けると共に植生基盤13を備えた浮き島11を複数浮かべて、植生基盤13に水生植物を植え付けて植生を成長させるようにする。これによっても図2に示す植生7と同様の浄化効果が得られる。
【0031】
ここで、いくつかの浮き島11に搭載させる植生基盤13は、できればこの閉鎖性水域2の底泥を用いることがよい。水質が改善されると、その土壌中の種子が発芽成長する可能性があるからである。一般に利水される湖沼などにおいては護岸工事がなされて、水深が深くなったりしており、水質の悪化も加わって、水生植物の生育は適さなくなっている場合がある。このような場合には底泥中には生息できなくなった植物の種子が休眠していることがあるためである。
【0032】
このような種子を含む植生基盤13を浮き島11に設置して水位を生育環境にあわせて調節することにより、種子が発芽する可能性があり、閉鎖性水域2が有する生態系の部分的回復が可能である。このような例を文献(環境資源、02年5月号Vol38.No6、P83〜P88「超電導磁気フィルタと植生を適用した、河川水浄化複合システム」)にみることができる。
【0033】
上述したように第一、第二浄化設備5、30を配置しているので、浄化設備の設置スペースを小さくできる。特に、都市部に近い湖沼における実施化を容易にできる。
【0034】
次に、仕切り体10の詳細を、図2および図4を参照しながら説明する。第一の仕切り体10は、複数の仕切り板20と、水中で縦になるように仕切り板20の下端部に取付けられた重錘22と、複数の浮き部材23と、仕切り板20が水中で上下に並ぶように仕切り板20に連結して取付けられると共に浮き部材23とを備えて構成されている。複数の仕切り板20は、ほぼ水面から湖底まで並ぶように配列されている。仕切り板20浮き部材23は複数の仕切り板20が水中に保持されるように浮力を有して構成されている。
【0035】
仕切り体10は湖沼の一部を仕切るものであり、河川の流入による直接間接の湖内水流の影響を受け難い湖岸に沿って設置することが望ましい。洪水時など河川流入量が増大したとき、第一の仕切り体10がその水圧を受けて流されたり損傷を受けたりしないようにするためである。また、一方、流入河川1からは木材など種々の物体が流れ込むので、これらに耐えることができるように浮き部材23等の外周は金属製網状部材等(図示せず)で保護することが望ましい。
【0036】
次に、図2に示す生物処理設備30を具体的に説明する。浄化領域6内に設ける第二の浄水領域6b内の仕切り体14は、湖沼が遠浅の場合においては特に自然景観を生かして木製杭などが望ましい。また、一般に水生植物(抽水性、浮漂性、浮葉性、沈水性植物を含む)のうちの特に浮標性及び浮葉性植物は高波や、底泥の巻上などに対して抵抗力が弱いので、できるだけ湖面を伝播する波や湖内の水流を直接受けないような仕切り体14を配置することが望ましい。木製の杭を並行に隣接して配置したり、ホダ木(図示せず)を周囲に巡らせて固定したりすると消波できる。
【0037】
次に、図3に示す生物処理設備30について具体的に説明する。浮き島11の場合においては、浮島11が、湖内水流によって流されたり、波によって大きくゆれたりしないようにアンカー15などで湖底にしっかり固定することが必要である。係留方法として、岸に係留ロープ(図示せず)で固定してもよい。また、浮島11内の水位は外水に連通するように、水の出入り管16を設けて浮島11内の水面を一定にする工夫が必要である。これらの浮き島11で生育した植物は、窒素除去目的に植生した場合においては秋季、冬季の枯れ死時に刈り取りして、湖沼外に搬出、処理する維持管理も必要である。このようにすれば、生物処理設備30及びその貯留水域6内には徐々に生物の生息空間(ビオトープ)が形成できるようになると考えられる。
【0038】
次に、リン酸塩などの汚濁物質を分離除去する超電導式磁気分離装置5について説明する。超電導式磁気分離装置5は省エネルギーで高速浄化が可能なため、コンパクトである。したがって、一般に流入河川の河口付近の狭隘なスペースにも設置できるものである。取水点近くに設置できるので、取水点と装置間の距離が短くなり、浄化装置において大きな消費動力を占める取水動力を低減できるメリットもある。
【0039】
以下、超電導式磁気分離装置の構成機能を図5から図7を参照しながら説明する。
【0040】
図5は空心ソレノイド型マグネットを鉛直に配置して、上端に近接して回転フィルタが配置される磁気分離装置において、強磁性体で構成されたマトリックス群101を装着して中心軸102を軸に回転することで連続処理が可能なディスク型回転フィルタ103が真空断熱容器104に格納された液体ヘリウム冷却式超電導マグネット105の空心軸の上側延長上に配置された磁気分離装置の縦断面構造図である。図6は図5に示すB−B矢視の水平断面図である。ドーナツ状のマトリックス群101がディスク型回転フィルタ103に装着されていることを示している。ディスク型回転フィルタ103は超電導マグネット105の上側に配置されている。超電導マグネット105によるマトリックス群101の磁気吸引支持力を超電導マグネット105の自重とバランスさせることによって、真空断熱容器104内に設けられる超電導マグネット105の支持構造(図示せず)に加わる支持力を低減できるので超電導マグネット105の真空断熱容器104内の支持構造が簡素化され、超電導マグネット105のイニシャルコストを低減することができる。また、超電導マグネット105はその空心軸上側延長上に配置されているディスク型回転フィルタ103のマトリックス群101部に磁性粉の飽和磁束密度以上の高磁場を発生することができ、さらにマトリックス群101に高勾配磁場を確保できる網目構造磁性体を用いることで、低濃度(例えば被処理水汚泥濃度の5〜10%)磁性粉注入量でも磁気分離が可能になるので、ランニングコストが低減できる。さらに、図示していないが超電導マグネット105には電源と永久電流スイッチが接続されており、永久電流モードでの運転により、ランニングコストの低減ができる。
【0041】
本実施例の磁気分離の動作は次のとおりである。前処理で生成された磁性凝集体を含む被処理水106は超電導マグネット105のボア内を通る通水管110内に下側107から流入して上向きに流れ、空心軸の上側延長上に配置されたディスク型磁気フィルタ103に装着されたマトリックス群101を通過する時点で被処理水106中の磁性凝集体がマトリックス群101に吸着されて浄化水流出口108から浄化水が流出する。磁性凝集体を吸着したマトリックス群101を装着したディスク型回転フィルタ103は電源に接続された電動機109の駆動力を受けて中心軸102を軸に回転し、通水管110側で磁性凝集体を吸着したマトリックス群101は通水管110側とは反対側の洗浄部に回転移動する。洗浄部ではディスク型回転フィルタ103の上側に配置された散水間111から浄化水を散水することでマトリックス群101に付着した磁性凝集体などの粒子群を剥離させる。洗浄部の磁場強度は真空断熱容器104の外周に設けられた鉄シールド112によって低減されており、マトリックス群101に付着した磁性凝集体などの粒子群は容易に離脱させることができる。マトリックス群101の構造は網状磁性ステンレス鋼が縦または横または斜めまたは同心形状またはそのいずれかの組合せで積層された構造として高勾配磁場の確保を可能とし、超電導マグネット105の発生磁場を超電導マグネット105の空心軸延長上に配置されているマトリックス群101部で磁性粉の飽和磁束密度(約0.5T)以上の磁場とすることで、高勾配磁気分離装置を提供することができる。洗浄部でマトリックス群101から剥離した粒子群は洗浄部下側の集泥容器113で集泥され送泥管114を通って濃縮槽115に流下し、そこで沈降濃縮された汚泥115は汚泥引抜き口116から引抜くことができる。このように磁気分離マトリックス群101を真空断熱容器104の上部に配置することによって、集泥容器113及び濃縮槽115をほぼ真空断熱容器104に略平行に配置できるのでディスク型磁気フィルタ103を超電導マグネット105の下側に配置する場合に比べて装置全体の高さを高くせずに濃縮槽115の高さも大きくとれるので汚泥濃縮度をより高めることができる。濃縮槽115のオーバーフロー取出し口117からは粒子群が沈降分離された上澄水を取出すことができ、集泥容器113から濃縮槽115への流下量はオーバーフロー調整弁118調整と汚泥引抜き口116からの引抜き量調整により調節が可能である。この場合には、集泥容器113から濃縮槽115への流下量は注水ポンプ125の吐出し配管途中に設けられた流量調整弁124で調整される吐出し量と汚泥引抜き口116からの引抜き量調整でほぼ決まる。また、汚泥濃縮槽115の上澄水は配管117から流量調整弁118を経て、原水槽(同図中には示さず)へもどされる。散水管111の上流側には逆止弁119がとりつけられて逆流を防いでいる。また、集泥容器113の側壁の傾斜角度は沈降する粒子の安息角よりも大きな角度をとることにより粒子群は集泥容器113内に堆積することなく、濃縮槽115へ沈下する。また、濃縮槽115も濃縮粒子の安息角より大きな角度をとることにより、重力によって濃縮された汚泥を汚泥引抜き口116から取出すことができる。回転フィルタ103は固定のフィルタケース120の中に格納され、外部への水密は隔壁によって保たれている。回転フィルタ103は中心軸102を中心に変速可能な電動機109の駆動力により連続または断続で回転でき、中心軸102がフィルタケース120を貫通する部分は軸封機構により水漏れのない構造になっている。電動機109は超電導マグネット105から距離を離して配置し、例えばチェーンやベルトやシャフトなどを介して磁気フィルタを駆動してもよい。真空断熱容器には仕切弁121を介して液体ヘリウムを注入するための注入口122とヘリウムガスの安全弁123が設けられており、超電導マグネット105がクエンチした時などは、ヘリウムガスは安全弁123に接続されている導管を通って安全な場所へ放出される。散水量調整弁124と逆止弁119の配置順は本実施例と逆でも支障はない。本実施例によれば、磁気分離装置の構造が簡素化されるばかりでなく、高磁場でかつ高勾配磁場を保持できるフィルタ構造により磁性粉注入量を大幅に低減することができ、さらに、洗浄剥離した磁性凝集体が濃縮により減容化されることにより磁性粉回収処理や汚泥脱水などの後処理設備を小型化することもできるので、イニシャルコスト、ランニングコストの低減が可能である。
【0042】
図7は図5、図6および磁性粉回収再利用を含む磁気分離システムの実施例のフローであり、大きく分けると取水手段、送水手段、添加剤注入手段、フロック形成手段、磁気分離手段、浄化水放流手段、磁性粉回収再利用手段、汚泥脱水手段で構成される。リン酸塩やアオコなどの汚濁物を含んだ原水は取水手段により湖沼などから取水され、送水手段により磁気分離手段に送られる。磁気分離手段までの送水経路では、添加剤注入手段により磁性凝集体の生成に必要な添加剤が注入され、フロック形成手段では磁性粉と汚濁物との集合体である磁性凝集体が生成される。汚濁物質が溶解性無機リン酸の場合には、凝集添加剤と化学反応して不溶性の金属塩が作られ、凝集体が生成される。磁気分離手段では磁性凝集体を含んだ被処理水から磁性凝集体が分離、濃縮され、浄化水は浄化水放流手段により放流または希釈水として再利用される。濃縮された磁性凝集体は磁性粉回収再利用手段で磁性粉と汚濁物の汚泥とに分離されて磁性粉は再利用される。汚泥は汚泥脱水手段で脱水され、脱水汚泥となる。
【0043】
取水手段はスクリーン128、取水槽129、取水ポンプ130などで構成され、リン酸塩、固形浮遊物などの汚濁物が含まれた原水131はスクリーン128を通過して取水槽129に流下し、取水槽129中に設置された取水ポンプ130によって取水されて原水タンク132に送られる。スクリーン128では原水中に浮遊する粗大なゴミなどが予め除去され、除去されたゴミなどは廃棄処分される。取水ポンプ130は水中ポンプであり、取水槽129および原水タンク132にそれぞれ設けられた水位計に連動して制御される。133は送水管であり、取水ポンプ130の吐出口から原水タンク132に接続され、その間には仕切弁と逆止弁が接続されている。
【0044】
送水手段は原水タンク132、原水攪拌機134、送水ポンプ136、送水管136などで構成され、原水タンク132には取水手段で取水された原水と図5で説明した濃縮槽115の上澄水と汚泥脱水手段の分離水などの被処理水が流入し、原水攪拌機134により汚濁物濃度の均一化および汚濁物の沈積防止が図られる。被処理水は原水タンク132に導管で接続された送水ポンプ135によって原水タンク132から引抜かれ、送水ポンプ135の吐出口に接続された送水管136を通って添加剤注入手段、フロック形成手段を経て磁気分離手段に送られる。送水管136には、流量調整弁137、逆止弁138、流量計139、濁度計140、圧力計141が接続されている。また、送水管は途中で分岐して被処理水の一部を原水タンク132に返水することで送水量の調整や原水タンク132内の攪拌を行なうこともでき、調整弁142で調整された被処理水は返水管143を通って原水タンク132に返水される。返水管の途中には逆止弁が設けられて逆流が防止されている。送水ポンプ135は原水タンク132に設けられた水位計に連動しており、原水タンク132の水位が異常低下した際は停止して送水ポンプ135の故障などの事故が未然に防止される。
【0045】
添加剤注入手段は磁性粉注入手段と無機凝集剤注入手段とpH調整剤注入手段と高分子凝集剤注入手段で構成されている。磁性粉注入手段に磁性粉ホッパー144、磁性粉フィーダ145、希釈水注水管146、磁性粉スラリー攪拌機147が備えられており、磁性粉は磁性粉ホッパー144に貯蔵され、磁性粉ホッパー144から磁性粉ホッパー144の下部に設けられた磁性粉フィーダ145によって磁性粉希釈タンク148に投入される。希釈水は浄化水タンク149から浄化水ポンプ150により希釈水注水管146を通って磁性粉希釈タンク148に注入され、磁性粉希釈タンク148に設けられた磁性粉スラリー攪拌機147によって磁性粉と混合されることで磁性粉スラリーが補充される。磁性粉ホッパー144には磁性粉投入口151と回収磁性粉投入手段152が接続されており磁性粉が補充される。磁性粉フィーダ145は磁性粉希釈タンク148に設けられた水位計と投入量積算計153に連動し、磁性粉希釈タンク148の液面水位が所定の位置まで低下すると運転が開始され、投入量積算計153で所定量が積算されると運転が停止される。希釈水注入管146には積算流量計145と電磁弁155が接続されており、電磁弁155は磁性粉希釈タンク148の水位計と積算流量計154に連動し、磁性粉希釈タンク148の液面水位が所定の位置まで低下すると開いて注水が開始され、積算流量計154で所定の流量が積算されると閉じて注水が停止される。また、磁性粉スラリー注入ポンプ156は磁性粉希釈タンク148の水位計に連動し、磁性粉希釈タンク148の液面水位が異常低下した際は停止して磁性粉スラリー注入ポンプ156の故障などの事故が未然に防止される。磁性粉ホッパー144には図示していないがアーチブレーカーが設けられ、乾燥空気が送られている。磁性粉フィーダ145にはスクリューフィーダやテーブルフィーダが用いられる。
【0046】
無機凝集剤注入手段は無機凝集剤貯留タンク157に貯留された無機凝集剤を無機凝集剤注入ポンプ158、無機凝集剤注入管159で送水管136に注入する手段である。無機凝集剤貯留タンク157には無機凝集剤攪拌機160が設けられ、無機凝集剤貯留タンク157内の無機凝集剤濃度の均一化や沈積防止が図られる。無機凝集剤注入ポンプ158は容積式定量ポンプであり、無機凝集剤貯留タンク157に設けられた水位計に連動し、無機凝集剤貯留タンク157の液面水位が異常低下した際は停止して無機凝集剤注入ポンプ157の故障などの事故が未然に防止される。また、前記磁性粉注入量制御手段に無機凝集剤注入量調節機能を付加して無機凝集剤注入ポンプ158に接続することで被処理水の汚濁物量に合わせて無機凝集剤注入量を制御することも可能である。無機凝集剤には硫酸バン土や鉄系の無機凝集剤が用いられ、補充口161から無機凝集剤貯留タンク157に補充される。無機凝集剤注入管159は逆止弁を介して送水管136に接続されている。
【0047】
pH調整剤注入手段はpH調整剤貯留タンク162に貯留されたpH調整剤をpH調整剤注入ポンプ163、pH調整剤注入管164で送水管136に注入して被処理水のpHを凝集に適した値に調整する手段である。pH調整剤貯留タンク162にはpH調整剤攪拌機165が設けられ、pH調整剤貯留タンク162内のpH調整剤濃度の均一化と沈積防止が図られている。pH調整剤注入ポンプ162は容積式定量ポンプであり、pH調整剤貯留タンク162に設けられた水位計に連動し、pH調整剤貯留タンク162の液面水位が異常低下した際は停止してpH調整剤注入ポンプ163の故障などの事故が未然に防止される。また、pH計とpH調節計を用いてpH調整剤注入ポンプの吐出量を制御することで被処理水のpH制御も可能である。pH調整剤には水酸化ナトリウム溶液や水酸化カルシウム溶液が用いられ、補充口166からpH調整剤貯留タンク162に補充される。pH調整剤注入管164は逆止弁を介して送水管136に接続されている。
【0048】
高分子凝集剤注入手段は高分子凝集剤ホッパー167、投入量積算計168、高分子凝集剤フィーダ169、高分子凝集剤溶解タンク170、171、高分子凝集剤攪拌機172、173、高分子凝集剤注入ポンプ174、175などで構成される。高分子凝集剤は高分子凝集剤ホッパー83に貯蔵されており、高分子凝集剤ホッパー167から高分子凝集剤ホッパー167の下部に設けられた高分子凝集剤フィーダ169により高分子凝集剤溶解タンク170または171に投入され、希釈水は浄化水タンク149から浄化水ポンプ150により希釈水注水管176または177を通って高分子凝集剤溶解タンク170または171に注入される。高分子凝集剤溶解タンク170または171では高分子凝集剤攪拌機172または173によって希釈水に高分子凝集剤が溶解される。高分子凝集剤の溶解には1時間程度の時間を要するため、高分子凝集剤溶解タンク170、171では溶解と貯留が交互に行われ、タンクの容量はそれぞれ1時間使用容量以上にされており、貯留されている側の高分子凝集剤溶解タンクから高分子凝集剤注入ポンプ174、175と高分子凝集剤注入管176、177によって送水管136または汚泥脱水手段に注入される。高分子凝集剤ホッパー167には高分子凝集剤投入口178から高分子凝集剤が補充される。高分子凝集剤フィーダ169は高分子凝集剤溶解タンク170または171に設けられた水位計と投入量積算計168に連動し、高分子凝集剤溶解タンク170または171の液面水位が所定の位置まで低下すると投入が開始され、投入量積算計168で所定量が積算されると投入が停止される。また、高分子凝集剤フィーダ169は投入先を切替えられる機構を有しており、投入先を高分子凝集剤溶解タンク170または171に切替えることができる。高分子凝集剤ホッパー167には図示していないがアーチブレーカーが設けられ、乾燥空気が送られており、高分子凝集剤ホッパー167にはスクリューフィーダやテーブルフィーダが用いられる。希釈水注入管には積算流量計179と電磁弁225が接続されており、電磁弁225は高分子凝集剤溶解タンク170または171の水位計と積算流量計179に連動し、高分子凝集剤溶解タンク170または171の液面水位が所定の位置まで低下すると開いて注水が開始され、積算流量計179で所定の流量が積算されると閉じて注水が停止される。さらに、希釈水注入管は希釈水注入管176と希釈水注入管177に分岐して高分子凝集剤溶解タンク170または171の水位計に連動して開閉する電磁弁180または181を介して高分子凝集剤溶解タンク170または171に接続され、電磁弁180または181は液面水位が所定の低水位位置まで低下したとき開いて希釈水が注入され、所定の高水位位置まで上昇したとき閉じて希釈水の注入が停止される。高分子凝集剤注入ポンプ174、175は容積式の定量ポンプであり、高分子凝集剤溶解タンク170または171の水位計に連動し、高分子凝集剤溶解タンク170または171の液面水位が異常低下した際は停止して高分子凝集剤注入ポンプ174、175の故障などの事故が未然に防止される。高分子凝集剤注入ポンプ174、175それぞれの吸込口は高分子凝集剤溶解タンク170と171に並列に接続されており、弁182と183を切替えて貯蔵が行われている高分子凝集剤溶解タンクを選択して高分子凝集剤を引抜くことができる。弁182、183には電磁弁や電動弁などを用いられ、高分子凝集剤溶解タンク170、171の水位計と連動させることで開閉制御が可能である。高分子凝集剤注入管176,177の管路の途中には逆止弁が接続され逆流が防がれている。
【0049】
フロック形成手段は送水管136が接続された急速攪拌機184と緩速攪拌機185で構成され、急速攪拌機184と緩速攪拌機185に接続されている導管には高分子凝集剤注入管176が接続されて高分子凝集剤が注入される。添加剤注入手段で添加剤が注入された被処理水は送水管136を通って急速攪拌機に送られ、添加剤と汚濁物(例えば、固形浮遊物、リン酸塩類、溶解性重金属類、大腸菌などのバクテリアなど)が被処理水中に均一に分散されてマイクロフロックが生成された後、被処理水に高分子凝集剤が注入されて緩速攪拌機によって磁性凝集体が形成される。急速攪拌機には可動部がないスタティックミキサーが用いられ、緩速攪拌機には所定容量の密閉攪拌槽と攪拌機が用いられるが、双方にスタティックミキサーを使用したり、管路式攪拌装置を用いることも可能である。
【0050】
磁気分離手段は図5及び図6で説明した磁気分離装置によるものであり、磁性凝集体を含む被処理水は緩速攪拌機185から磁気分離部の通水管110に接続された導管186によって磁気分離装置に送られ磁性凝集体が磁気分離された後、浄化水は導管187を通って浄化水タンク149に送られる。磁気分離装置で使用される洗浄用水は加圧ポンプ188から散水管111に送られ、洗浄水配管には、逆止弁119、流量調整弁124、流量計126、が設けられている。磁気分離装置の濃縮槽115から取出される上澄水は濃縮槽の上澄水取出口から分離水タンク189に接続された導管190によって分離水タンク189に送られ、導管190の上澄水取出口側には流量計191と調整弁118が設けられて上澄水取出量を調整することができる。濃縮槽115で濃縮されて減容した汚泥は磁性粉回収再利用手段に送られる。磁気分離装置の真空断熱容器の安全弁からのヘリウムガスは安全弁に接続された導管192を通って安全な放出口193から大気に放出される。
【0051】
浄化水は磁気分離手段で得られた浄化水を湖沼などに放流を主として、ディスク型回転フィルタ103の洗浄水の他、磁性粉や凝集剤の希釈水として利用される。浄化水の一部が希釈水として利用されるため、一旦浄化水タンク149に貯留されて浄化水ポンプ150と放流管194によって放流される。放流管194は管路の途中で希釈水送水管195に分岐されて浄化水の一部が添加剤注入手段の希釈水として利用される。浄化運転開始前など浄化水タンク149が空であったり、水量が少ない場合は浄化水タンク149に水道水を必要量補充しておくことで運転開始時のディスク型回転フィルタ103の洗浄水及び希釈水は確保される。水道は水道水接続口196に接続され、弁を介して浄化水タンク149に注入される。放流管194、希釈水移送管195にはそれぞれ調整弁197、198が接続されており、放流管194から希釈水移送管195への浄化水分配圧力を調整することができ、逆止弁により逆流防止が図られている。また、浄化水ポンプ150と希釈水移送管195分岐点の間の管路には圧力計199が設けられ、放流圧力を監視することができる。浄化水ポンプ150は浄化水タンク149に設けられた水位計に連動し、浄化水タンク149の液面水位が異常低下した際は停止して浄化水ポンプ150の故障などの事故が未然に防止される。その他、浄化水放流先が浄化水タンク149よりも低かったりして放流に浄化水ポンプ150が必要ない場合、浄化水ポンプ150は希釈水送水用のみに用いて、放流は浄化水タンク149からのオーバーフローを導管により放流先に流下させれば浄化水ポンプ150を小型化することができ、さらに希釈水送水用にも浄化水ポンプ150が必要ない場合、浄化水ポンプ150は不必要となり、装置を簡素化することができる。ディスク型回転フィルタ103の洗浄水も同様に浄化水タンクから洗浄水加圧ポンプによって送水される。洗浄水配管途中には洗浄流量計126、流量調整弁124、逆止弁119が配置されて、洗浄流量の調整や、磁気分離本体からの逆流を防止している。
【0052】
磁性粉回収再利用手段では磁気分離手段の濃縮槽下部から引抜かれた磁性凝集体の汚泥が磨砕機200で磨砕されて汚濁物と磁性粉に純度よく分解された後、汚泥ポンプ201、汚泥移送管202によって磁選機203に送られ、磁選機203を通過した汚泥は導管204を流下して汚泥タンク205に入り、磁選機203で回収された磁性粉は回収磁性粉投入手段152を通って磁性粉ポッパー144に補充されて再利用される。磨砕機200にはホモミクサが用いられ、入口と出口をバイパスする導管206とその管路中の弁207により汚泥の一部を連続循環させることができるので分解純度を高めることができる。また、本例では磨砕機200の後段に汚泥ポンプ201を設置しているが、汚泥ポンプ201の後段に磨砕機201を設置しても差し支えない。濃縮槽115から磨砕機200、汚泥ポンプ201を経て磁選機203に送られる汚泥量は汚泥移送管202に設けられた弁によって調整される。磁選機203は永久磁石が埋め込まれた電動機駆動の回転円板と磨砕汚泥が入る分離槽、円盤の永久磁石に吸着された磁性粉を掻き取るスクレーパーを備え、回転円板の一部分が分離槽の汚泥に浸されて回転し、分離槽に入った汚泥が反対側の溢流側に向かって流れて溢流するまでの間に回転円板の永久磁石で磁性粉が吸着され、吸着した磁性粉は回転円板の回転とともに空気中に移動してスクレーパーで掻き取られ、回収される。また、回転円板の外周と分離槽の内壁には攪拌翼が設けられており、回転円板が回転することで分離槽内の汚泥が攪拌されて磁性粉の沈積が防がれている。回収磁性粉投入手段152には例えばスクリューフィーダやベルトコンベアなどを用いることができるが、磁選機203を磁性粉ホッパー65の磁性粉投入口の真上に配置して、回収された磁性粉が重力落下で磁性粉ホッパー144に投入されるようにすれば、回収磁性粉投入手段152は不必要になって装置をさらに簡素化することができる。また、磁選機203を磁性粉希釈タンク148の真上に配置して、回収された磁性粉が重力落下で磁性粉希釈タンク148に投入されるようにしても、回収磁性粉投入手段152を省略することができ、装置を簡素化することができる。
【0053】
汚泥脱水手段は汚泥脱水機208によって汚泥を脱水して減容化するとともに、汚泥運搬を容易にするための手段で、汚泥は汚泥タンク205から汚泥供給ポンプ209、供給管210により汚泥脱水機208に供給される。汚泥脱水機208には添加剤注入手段からの高分子凝集剤注入管177が接続されて高分子凝集剤が注入されており、脱水汚泥は汚泥排出口からシューター211に落とされて汚泥フィーダ212により汚泥回収容器213に移送され、分離水は導管214を通って分離水排出口から分離水タンク189に流下して磁気分離手段の濃縮槽上澄水とともに分離水ポンプ215、導管189によって原水タンク132に送られる。汚泥供給ポンプ209はフリクトスイッチ付きの水中スラリーポンプで、汚泥タンク205の汚泥液面が異常低下した際は停止して汚泥供給ポンプ209の故障などの事故が未然に防止される。また、分離水ポンプ215はフリクトスイッチ付きの水中ポンプで、分離水タンク209の水位が異常低下した際は停止して分離水ポンプ215の故障などの事故が未然に防止される。供給管210の管路の途中にはスラリー流量計216と流量調整弁217が設けられている。また、導管216の管路の途中には流量計218、弁219、逆止弁が接続されている。汚泥回収容器213に貯まった脱水汚泥220は、例えば廃棄物処分場など運搬されて処分されたり、また、コンポストの原料としてリサイクルすることができる。特に、磁性鉄粉を回収再利用しない設備においては汚泥中の鉄分含有量が高くなるので、鉄分が必要なセメントの原材料としてリサイクルすることもできる。
【0054】
その他、本実施例で用いられるタンクには全てレベルゲージ、オーバーフロー管、ドレン管が設けられており、オーバーフローおよびドレンは全て排水溝に集められて、例えば下水に排水される。また、本実施例で用いているタンク類に鉄筋コンクリート製の槽用いることも可能である。図では制御盤が省略されているが本実施例を構成している機器や装置は全て制御盤から電源の供給を受け、運転操作やシーケンス制御が行われている。ここで、本設備の電力は通常の商用電源を利用してもよいし、特別にこの設備用として、風力発電、ソ−ラ−発電、バイオマス発電、燃料電池発電設備などの発電設備を設置してこれらを単独又は、組み合わせて供給することもできる。本実施例によれば磁気分離装置の構造簡素化、磁性粉注入の低濃度化および磁性粉の回収再利用により、低コストで運転員の運転操作が簡略化された省スペ−ス、省エネルギ−の磁気分離装置を提供することができ、湖沼など閉鎖性水域のリンや浮遊固形物の浄化に好適である。
【0055】
次に第二の浄化工程である窒素の除去のための植生設備は以下のようなものである。水生植物を栽培する植生設備は、植物体による窒素除去などの水質浄化効果と、生態系を創出することの二つが期待できる。第一の浄化工程でリンなどを分離除去された処理水中の有機性窒素は、ここでは、植物に付着する微生物により分解され、アンモニアさらには、亜硝酸態・硝酸態窒素などの無機塩に変換される。植物は、太陽エネルギ−を利用して、これらの無機塩を吸収しながら、成長するため、窒素成分は植物体に取り込まれ、水域から除去される。また、植物体の表面に付着した生物群も、有機物の分解や栄養塩類の除去に重要な役割を果たしている。
【0056】
各植物の水質浄化試験における富栄養化物質の窒素、リンに関する植物の除去速度の測定例を表1に示す。
【0057】
【表1】

Figure 0003939664
前記のリンなど除去のための第一浄化工程に用いられる超電導磁気分離装置5においては、設置スペ−スは処理水量5000m3/日(人口約2万人分の水道給水量に相当)の装置の場合、設置スペ−スは約300mで、 リン除去率は85%以上が得られる。一方、第二浄化工程である植生浄化設備7において、窒素の除去を行なう場合、水量5000m3/日を浄化するために必要な植生面積は、ヨシの場合、原水中の窒素濃度を10PPMとすると、約50万mのヨシ原で67%の窒素が除去できる計算である。この必要面積は第一のリンの浄化工程に比べて、桁違いの広大なスペ−スになる。
【0058】
しかし、これだけの植生面積を確保できなくても、富栄養塩の一方のリンが除去されたことによって、成長、繁殖ができなくなっていた植物の成長にとってより好ましい環境に整えられるので、水中の窒素及び残存リンを栄養源として成長できるようになる。それは、アオコなどの藻類は栄養塩、光、水温、炭酸ガス、水の循環等の一定の条件が一つでも欠けると繁殖が抑制されることがわかってきたからである。
【0059】
したがって、現実的には植生7の設置スペ−スの制約から、リン除去装置の処理水の全量を対象に窒素を分離除去することは難しいが、超電導式磁気分離装置5の処理水の一部分について植生7で浄化しても目的の一部を達成することが可能である。このため、第一浄化工程で汚濁物質を分離除去された処理水の大部分については第二浄化工程をバイパスさせることでもよい。図1の俯瞰図はそのような例を示し、第二浄化工程を実施する第二の浄水領域6bの周囲を取り囲むように仕切り体14を配置し、第二浄化工程の第二の浄水領域6bの沖側を迂回して貯留水が流下できるようにしたものである。
【0060】
ここで、このバイパス水路第一の浄水領域6aと植生帯第二の浄水領域6bについては水が交じり合っても、問題はなく、湖沼2から仕切った浄化領域6を介して伝播してくる水流や、波浪を防げる程度の仕切り体14で十分である。また、浄化領域6内においては、その外の湖沼水との仕切り体10によって水が混じりあうことがある程度抑えることができれば十分である。逆に仕切り体10に少量の水の出入りを許容することにより、河川流や吹送流による仕切り体10への外力が緩和され、仕切り体10の流出を防止することができる。
【0061】
また、例えば、水道水源の場合、夜間の取水量が減った場合などにおいても、超電導式磁気分離装置5の運転を継続して行なえば、浄化領域6内の貯留水は増加して、その外部の湖沼2へ流出し、湖沼の希釈水として浄化にも寄与できる。さらには、河川水の浄化だけでなく、湖内の底泥の浚渫除去も同時に実施すると、より効果的である。富栄養湖沼は底層付近は貧酸素状態になり、堆積したリンや窒素などが底泥から溶出してさらに栄養塩負荷に加わるからである。
【0062】
その他、第一浄化工程では凝集沈殿ろ過方法なども適用が可能である。この方法においてはリン酸塩や浮遊固形物などを除去できるからである。
【0063】
本実施形態によれば、湖沼などの閉鎖性水域2に河川などから流入する水の一部を取水し、この水を物理化学的に処理して主にリンを除去する第一の浄化工程と、閉鎖性水域2を深さ方向に仕切って形成した浄化領域6に第一の浄化工程で処理された処理水を導入し、この処理水を浄化領域6内で生物処理して主に窒素を除去する第二の浄化工程とからなるので、湖沼などの浄化領域6でのリンや窒素などの汚染物質による富栄養化を抑制して良質利水のための水源を得るとともに浄化領域6の親水性および本来の生態系を回復させることができる。
【0064】
さらに、超電導式磁気分離装置5を用いて物理化学的処理しているので、高速高効率なリン分離除去ができ、これによって水質浄化における大幅な省スペース化および省エネルギー化を図ることができる。
【0065】
さらに、植生を用いた生物処理を行なっているので、閉鎖性領域2内の特定部分を構成する浄化領域6の景観を良好にしつつ、本来の生態系を回復させることができる。
【0066】
また、湖沼などの閉鎖性水域2に河川などから流入する水の一部を取水し、この水を超電導式磁気分離処理して主にリンを除去する第一の浄化工程と、閉鎖性水域2を深さ方向に仕切って形成した第一の浄化領域6aおよび第二の浄化領域6bに第一の浄化工程で処理された処理水を分流してそれぞれに導入し、第二の浄化領域6bに導入した処理水をその第二の浄化領域6b内で生物処理して主に窒素を除去する第二の浄化工程とからなるので、比較的貯留水量の大きな閉鎖性水域6の水質改善をより効果的にまた確実に遂行することができる。
【0067】
さらに、第二の浄化領域6bに隣接してこれを取り囲むように第一の浄化領域6aを設けているので、第一および第二浄化領域6a、6b内の処理水が流出入して混合することがあっても処理水同士の混合であり、第一の浄化領域6aが汚染されることなく、しかも第二の浄化領域6bにおける所定の浄化性能を確保することができる。
【0068】
【発明の効果】
本発明によれば、設備コスト、設置スペースおよび駆動エネルギーの最小化を図りつつ、湖沼などの浄化領域でのリンや窒素などの汚染物質による富栄養化を抑制することができる湖沼などの浄化方法及びその浄化システムを得ることができる。
【0069】
また、本発明によれば、比較的貯留水量の大きな閉鎖性水域の水質改善をより効果的にまた確実に遂行することができる湖沼などの浄化方法及びその浄化システムを得ることができる。
【図面の簡単な説明】
【図1】本発明の一実施例を示す湖沼などの浄化システムを適用した周辺部分の平面図である。
【図2】図1のA−A断面図である。
【図3】図2と異なる適用例の図1のA−A断面相当図である。
【図4】図1の浄化システムにおける仕切り体の一部分を示す側面図である。
【図5】図1の浄化システムにおける超電導式磁気分離装置の磁気分離部の構成図である。
【図6】図5の超電導式磁気分離装置の磁気分離メディアを示す断面図である。
【図7】図1の浄化システムにおける超電導式磁気分離装置のシステム構成を示したフロー図である。
【符号の説明】
1…流入河川、1a…河川水取水口、2…閉鎖性水域(湖沼など)、3…湖岸、4…流出河川、4a…越流せき、5…超電導式磁気分離装置(物理化学的処理設備)、5a…第一処理水放出口、6…浄化領域、6a…第一の浄化領域、6b…第二の浄化領域、7…植生、8…第一浄化工程水域、9…利水取水口、10…第一の仕切り体、11…浮き島、12…浮き島用フロート、13…浮島用土壌、14…第二の仕切り体、15…浮島用アンカー、16…浮島用水位調節連通管、20…仕切り板、21…鎖、22…重錘、23…浮き部材、30…生物処理設備。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a purification method and a purification system for lakes and the like, and purification technology for closed water areas such as eutrophied lakes, dam lakes, and harbors, in particular, closed water areas for tap water sources or landscapes for sightseeing, recreational use. The present invention relates to a purification technique for hydrophilic water areas.
[0002]
[Prior art]
In recent years, in the closed water areas such as lakes and marshes, which are water sources for water supply, the inflow of substances that cause eutrophication such as nitrogen and phosphorus has increased, and a eutrophication phenomenon has progressed in which algae are produced in large quantities and water quality deteriorates. Yes. Therefore, purification facilities using various technologies to purify the water area by suppressing eutrophication in closed water areas such as lakes and dam lakes as water sources or hydrophilic water areas are strengthened. I came.
[0003]
A number of technologies for purifying such closed waters have been proposed, but if these are classified, chemicals can be removed by mechanical removal of pollutants, technology by activating microorganisms, chemicals, etc. For example, a technology for processing in a closed manner, and a technology for processing by circulating a part of water in a closed water area.
[0004]
As one of the prior arts, for example, there is a water treatment method and apparatus disclosed in Patent Document 1. This Patent Document 1 discloses a water treatment method and apparatus for eutrophication in a closed water area, a treatment process and a treatment apparatus for removing algae generated along with eutrophication, and treatment with anaerobic microorganisms. Described is a water treatment method and apparatus comprising a treatment process and a treatment apparatus, a treatment process and a treatment apparatus for treating with an aerobic microorganism, and a treatment process and a treatment apparatus for removing phosphorus remaining by chemical treatment. Yes.
[0005]
Moreover, there exists a purification apparatus of the polluted water disclosed by patent document 2 as another prior art. In this Patent Document 2, a bubble recovery use frame with a float in which a plurality of concave cross-section ridges opened at the top are arranged at appropriate intervals on the inner water surface of a catamaran type carrier, It is connected to the draft state where the side edge is slightly above the surface of the water. A device for purifying polluted water is described which is provided to provide recovery means, remove suspended substances in water in closed water areas such as main lakes and seas, and purify water in the water areas.
[0006]
Furthermore, there exists a pond water purification equipment disclosed by patent document 3 as another prior art. This prior art is a pond water purification facility in a reservoir, irrigation reservoir, etc., in which a strainer and a water purification device are arranged on one side of the pond, and a hydrophilic zone in which gravel, sand, etc. are laid on the other side. A pond water purification facility is described in which a pond water that has been partitioned and purified by a water purification device is guided by a conduit to a hydrophilic zone through a man-made waterfall, and a water flow generator that generates a water flow toward the hydrophilic zone side strainer is placed in place. ing.
[0007]
[Patent Document 1]
JP-A-2-95498
[Patent Document 2]
Japanese Patent Laid-Open No. 5-287
[Patent Document 3]
Japanese Patent Laid-Open No. 4-90898
[0008]
[Problems to be solved by the invention]
However, substances such as phosphorus and nitrogen that promote eutrophication in closed water areas are mainly supplied from rivers that flow into the closed water areas. River water containing these substances flows into the closed water area and is diluted into the accumulated water there, so a large amount of water (water in the whole closed water area) must be treated with conventional purification methods and equipment. There wasn't. As a result, the above-described prior art has a problem that the production cost, installation space, drive energy, and the like of the purification equipment increase.
[0009]
An object of the present invention is to provide a purification method for lakes and the like that can suppress eutrophication due to contaminants such as phosphorus and nitrogen in a purification region such as lakes and marshes while minimizing facility costs, installation space and drive energy. And providing a purification system thereof.
[0010]
Another object of the present invention is to provide a purification method for lakes and the like and a purification system thereof that can more effectively and reliably perform water quality improvement in a closed water area with a relatively large amount of stored water. .
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the purification method for lakes and marshes of the present invention mainly takes a part of water flowing from a river etc. into a closed water area such as a lake and treats this water physicochemically. A first purification step for removing phosphorus, and the treated water treated in the first purification step is introduced into a purification region formed by partitioning the closed water region in the depth direction, and the treated water is introduced into the purification region And a second purification step in which nitrogen is mainly removed by biological treatment.
[0012]
In order to achieve the other object described above, the purification method for lakes and the like of the present invention mainly takes a part of water flowing from a river or the like into a closed water area such as a lake and performs superconducting magnetic separation treatment on the water. The first purification step for removing phosphorus and the first purification region and the second purification region formed by partitioning the closed water region in the depth direction are treated water treated in the first purification step. It consists of a second purification step in which the treated water introduced into the second purification region is diverted and biologically treated in the purification region to mainly remove nitrogen.
[0013]
The other means of the present invention will be clarified from the following description.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a purification method and a purification system for lakes and the like according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7.
[0015]
FIG. 1 is an overhead view of a purification target lake including a river flowing into the eutrophication lake as seen from above.
[0016]
In closed water areas 2 such as lakes, dam lakes, and harbors, a large amount of domestic wastewater and rainwater containing eutrophic substances such as phosphorus and nitrogen flows through the inflowing river 1. If appropriate measures against inflow load are not taken, eutrophic substances that flow into the closed water area 2 stay in the closed water area 2 and partly flow out from the outflow river 4, but most of the eutrophic substances are in the closed water area. 2 is accumulated. An overflow basin 4 a is provided in a portion of the outflow river 4 close to the closed water area 2.
[0017]
As a result, eutrophication of the water in the closed water area 2 proceeds, a large amount of algae are generated, the water quality deteriorates and the transparency is lowered, and the landscape is damaged. Such eutrophication will also significantly change the ecosystem. That is, there is a risk that the number of solids such as aquatic plants and insects growing in the closed water area 2, and fish and mammals depending on them may be reduced or extinct. Moreover, in the water supply which uses the said closed water area 2 as a water source, when using it as a water source of a water supply etc., the load increase of purified water supply equipment and the fall of supplied water quality (for example, musty odor etc.) will be caused.
[0018]
Therefore, in order to prevent eutrophication of the closed water area 2, it is necessary to separate and remove phosphorus, nitrogen components, suspended solids, and the like of the eutrophic substances contained in the river water flowing into the closed water area 2. . However, in general, the amount of inflow water from rivers varies greatly depending on the season, so it is difficult to purify the entire amount of inflow water from the viewpoint of economy. Moreover, the purification method differs between phosphorus and nitrogen. Nitrogen, in particular, needs to use the biological absorption action, and has a feature that it is difficult to remove at high speed compared to phosphorus, which can be removed by physicochemical in addition to the biological absorption action.
[0019]
For this reason, in designing an efficient purification method and system, how to set the elements of the amount of purified water and the removal rate of phosphorus and nitrogen minimizes construction costs and running costs, and maximizes the purification effect. We examined whether it could be limited.
[0020]
As a result, the following was found to be particularly effective. When the closed water area 2 is mainly used as a water source for water supply or agricultural water, the amount of water commensurate with the amount of water used is purified. Then, water in a state of high eutrophication substance concentration (that is, water in the inflowing river 1 or water immediately after flowing into the closed water area 2 from the inflowing river 1) is taken and purified. As a purification method, first, phosphorus and suspended solids that can be purified at high speed are removed by a physicochemical method, and then nitrogen is removed by biological treatment. Nitrogen removal provides a purification area in the closed water area 2 to prepare an environment in which plant growth and the natural purification ability inherent in the closed water area 2 can be exhibited.
[0021]
More specifically, in this embodiment, a river water intake 1a is installed near the mouth of the inflowing river 1 where the concentration of the eutrophic substance is the highest, and the necessary amount of water is taken from the river water intake 1a. Then, mainly phosphorus and suspended solids are purified through the superconducting magnetic separation device 5 constituting the physicochemical treatment facility. Details of this processing will be described later.
[0022]
The treated water treated by the superconducting magnetic separation device 5 is discharged and stored in the purification region 6 formed by partitioning the closed water area 2 with the first partition 10 through the first treated water discharge port 5a. In addition, if the 1st treated water discharge port 5a is said with respect to the purification | cleaning area | region 6, it will comprise the intake of treated water. The purification area 6 includes a plurality of purification areas 6a and 6b (in this embodiment, the first purification area 6a and the second water purification area 6b) formed by partitioning the purification area 6 with the second partition body 14. It is configured.
[0023]
The 2nd water purification area | region 6b is provided so that it may extend long from the inflow river 1 side to the outflow river 4 side along the lake shore 3. As shown in FIG. The first purification region 6a is provided adjacent to and surrounding the second purification region 6b. Therefore, the 1st water purification area | region 6a is extended long along the lake shore 3 via the 2nd water purification area | region 6b. The first treated water discharge port 5a is branched into a plurality, and the treated water is divided and discharged to the plurality of purification regions 6a and 6b. The 1st treated water discharge port 5a is installed so that it may be located in the edge part near the inflow river 1 side of the 1st water purification area | region 6a and the 2nd water purification area | region 6b.
[0024]
The water-use intake 9 is installed on the side of the reverse intake in the purification area 6 so that the treated water in the purification area 6 can be used as a water source such as tap water or agricultural water. In this embodiment, the water intake 9 is installed near the end of the first water purification area 6a on the side opposite to the water intake, and the treated water including both the first water purification area 6a and the second water purification area 6b is used as a water source. It can be used as.
[0025]
As shown in FIG. 2, the vegetation 7 is planted in the 2nd water purification area | region 6b. The vegetation 7 includes plants existing in the closed water area 2. A biological treatment facility 30 is constituted by the second partition 14 and the vegetation 7, and mainly nitrogen contained in the treated water flowing into the second water purification region 6 b is removed. The purified treated water flows out into the first purified water region 6a and is further taken out as utilization water from the water utilization inlet 9.
[0026]
In this way, phosphorus and nitrogen contained in the water of the inflowing river 1 are sequentially removed by the physicochemical treatment process by the superconducting magnetic separation device 5 and the biological treatment process by the vegetation 7, so that the eutrophic substance can be efficiently removed. Can be removed. And not only does it not be necessary to purify the entire closed water area 2 into which river water containing eutrophic substances has flowed in as in the prior art but to use it, but the nature that it originally has is restored in the second water purification area 6b. The possibility of being increased increases the hydrophilicity.
[0027]
With such a purification system configuration, it is possible to prevent at least a deterioration in the quality of water taken from the purification region 6. Furthermore, in the vegetation purification facility, the improvement of the water quality of the second water purification area 6b promotes the growth of aquatic plants that have conventionally inhabited the closed water area 2, and consequently the original second water purification area. A series of natural purification mechanisms will be restored in which the ecosystem of 6b is partially restored and water quality is further improved. Therefore, the progress of eutrophication is stopped also in the purification region 6 as a whole, and it becomes possible to improve to a useful water area such as water use and hydrophilic area.
[0028]
Here, even if the amount of river water increases in the rainy season or during flooding, the water taken by the superconducting magnetic separation device 5 is substantially isolated from the other areas of the closed water area 2 by the partition 10. Therefore, there is an advantage that the purification area 6 can be secured as a purified water area.
[0029]
The vegetation 7 shown in FIG. 2 is employed when the second water purification region 6b is shallow, and is configured by directly planting a plant such as a cocoon in soil in a shallow water region. The second partition body 14 shown in FIG. 2 rises from the bottom of the shallow region to form the second water purification region 6b.
[0030]
Further, when the water depth is deep and it is difficult to plant aquatic plants directly on the soil, as shown in FIG. 3, a plurality of floating islands 11 having a vegetation base 13 are floated and a vegetation base 13 is mounted. Plant aquatic plants to grow vegetation. This also provides a purification effect similar to that of the vegetation 7 shown in FIG.
[0031]
Here, the vegetation base 13 to be mounted on some floating islands 11 should preferably use the bottom mud of the closed water area 2 if possible. This is because if the water quality is improved, seeds in the soil may germinate and grow. In lakes and other areas where water is generally used, revetment work has been carried out, the water depth has become deeper, water quality has deteriorated, and aquatic plants can no longer grow properly. In such a case, the seeds of plants that can no longer live in the bottom mud may be dormant.
[0032]
By installing the vegetation base 13 including such seeds on the floating island 11 and adjusting the water level according to the growth environment, the seeds may germinate, and the partial recovery of the ecosystem of the closed water area 2 is achieved. Is possible. Such an example can be found in the literature (Environmental Resources, May 2002, Vol 38, No. 6, P83-P88 “River Water Purification Complex System Applying Superconducting Magnetic Filter and Vegetation”).
[0033]
As described above, since the first and second purification equipments 5 and 30 are arranged, the installation space for the purification equipment can be reduced. In particular, implementation in lakes near urban areas can be facilitated.
[0034]
Next, details of the partition 10 will be described with reference to FIGS. 2 and 4. The first partition 10 includes a plurality of partition plates 20, a weight 22 attached to the lower end of the partition plate 20 so as to be vertical in water, a plurality of floating members 23, and the partition plate 20 in water. It is connected to the partition plate 20 so as to be lined up and down and is provided with a floating member 23. The plurality of partition plates 20 are arranged so as to be lined up almost from the water surface to the lake bottom. The partition plate 20 floating member 23 is configured with buoyancy so that the plurality of partition plates 20 are held in water.
[0035]
The partition 10 partitions a part of the lake and is desirably installed along the lake shore which is not easily affected by the indirect lake water flow caused by the inflow of the river. This is to prevent the first partition 10 from being swept away or damaged by the water pressure when the amount of river inflow increases, such as during a flood. On the other hand, since various objects such as wood flow from the inflowing river 1, it is desirable to protect the outer periphery of the floating member 23 and the like with a metal net-like member (not shown) so as to withstand these.
[0036]
Next, the biological treatment facility 30 shown in FIG. 2 will be specifically described. The partition 14 in the second water purification region 6b provided in the purification region 6 is preferably a wooden pile or the like, taking advantage of the natural landscape, especially when the lake is shallow. In general, among buoyant and floating plants among aquatic plants (including water extractability, floatability, floatability, and subsidence plants), the resistance to high waves and rolling up of the bottom mud is weak. It is desirable to arrange the partition 14 so as not to directly receive the wave propagating on the lake surface and the water flow in the lake as much as possible. Waves can be extinguished by placing wooden stakes next to each other in parallel or by fixing a hodder tree (not shown) around the periphery.
[0037]
Next, the biological treatment facility 30 shown in FIG. 3 will be specifically described. In the case of the floating island 11, it is necessary to fix the floating island 11 firmly to the bottom of the lake with an anchor 15 or the like so that the floating island 11 is not washed away by the water current in the lake or greatly shaken by the waves. As a mooring method, you may fix to a shore with a mooring rope (not shown). Moreover, the water level in the floating island 11 needs to be devised so as to make the water surface in the floating island 11 constant by providing a water access pipe 16 so that the water level communicates with the outside water. When these plants grow on floating islands 11 are vegetated for the purpose of removing nitrogen, it is necessary to maintain them so that they are harvested in the fall and winter when they die and are taken out of the lake and processed. If it does in this way, it is thought that the living space (biotope) of a living body can be gradually formed in the biological treatment facility 30 and its storage water area 6.
[0038]
Next, the superconducting magnetic separation device 5 that separates and removes contaminants such as phosphate will be described. The superconducting magnetic separation device 5 is compact because it saves energy and can be purified at high speed. Therefore, it can generally be installed in a narrow space near the mouth of the inflowing river. Since it can be installed near the water intake point, the distance between the water intake point and the device is shortened, and there is an advantage that the water intake power that occupies a large power consumption in the purification device can be reduced.
[0039]
Hereinafter, the function of the superconducting magnetic separation device will be described with reference to FIGS.
[0040]
FIG. 5 shows a magnetic separation apparatus in which air-core solenoid magnets are arranged vertically and a rotary filter is arranged close to the upper end, and a matrix group 101 made of a ferromagnetic material is attached and a central axis 102 is taken as an axis. The disk-type rotary filter 103 that can be continuously processed by rotating is a longitudinal cross-sectional structure diagram of a magnetic separation device that is disposed on the upper extension of the air core shaft of the liquid helium cooled superconducting magnet 105 housed in the vacuum heat insulating container 104. is there. FIG. 6 is a horizontal sectional view taken along the line BB in FIG. It shows that the donut-shaped matrix group 101 is mounted on the disk-type rotary filter 103. The disk-type rotary filter 103 is disposed on the upper side of the superconducting magnet 105. By balancing the magnetic attraction support force of the matrix group 101 by the superconducting magnet 105 with the weight of the superconducting magnet 105, the supporting force applied to the support structure (not shown) of the superconducting magnet 105 provided in the vacuum heat insulating container 104 can be reduced. Therefore, the support structure of the superconducting magnet 105 in the vacuum heat insulating container 104 is simplified, and the initial cost of the superconducting magnet 105 can be reduced. The superconducting magnet 105 can generate a high magnetic field equal to or higher than the saturation magnetic flux density of the magnetic powder in the matrix group 101 of the disk-type rotary filter 103 disposed on the upper extension of the air core axis. By using a network structure magnetic material that can secure a high gradient magnetic field, magnetic separation is possible even with a low concentration (for example, 5 to 10% of the concentration of water sludge to be treated) of magnetic powder injection, so that the running cost can be reduced. Further, although not shown, a power source and a permanent current switch are connected to the superconducting magnet 105, and the running cost can be reduced by the operation in the permanent current mode.
[0041]
The magnetic separation operation of this embodiment is as follows. The treated water 106 including the magnetic aggregates generated in the pretreatment flows into the water pipe 110 passing through the bore of the superconducting magnet 105 from the lower side 107 and flows upward, and is disposed on the upper extension of the air core shaft. When passing through the matrix group 101 attached to the disk-type magnetic filter 103, the magnetic aggregates in the treated water 106 are adsorbed by the matrix group 101, and the purified water flows out from the purified water outlet 108. The disk-type rotary filter 103 equipped with the matrix group 101 that adsorbs the magnetic aggregates receives the driving force of the electric motor 109 connected to the power source and rotates around the central axis 102, and adsorbs the magnetic aggregates on the water pipe 110 side. The matrix group 101 rotates and moves to the cleaning unit on the side opposite to the water pipe 110 side. In the cleaning unit, particles of particles such as magnetic aggregates attached to the matrix group 101 are peeled off by spraying purified water from the sprinkling space 111 disposed above the disk-type rotary filter 103. The magnetic field strength of the cleaning unit is reduced by the iron shield 112 provided on the outer periphery of the vacuum heat insulating container 104, and particles such as magnetic aggregates attached to the matrix group 101 can be easily separated. The matrix group 101 has a structure in which a reticulated magnetic stainless steel is laminated vertically, horizontally, obliquely, concentrically, or any combination thereof, so that a high gradient magnetic field can be secured, and the generated magnetic field of the superconducting magnet 105 is used as the superconducting magnet 105. By setting the magnetic field to be equal to or higher than the saturation magnetic flux density (about 0.5 T) of the magnetic powder at 101 parts of the matrix group disposed on the air axis extension, a high gradient magnetic separation device can be provided. The particles separated from the matrix group 101 in the washing section are collected in a mud collection container 113 below the washing section, and flow down to the concentrating tank 115 through the mud pipe 114, where the sludge 115 concentrated and settled is the sludge extraction port 116. Can be pulled out from. By disposing the magnetic separation matrix group 101 in the upper part of the vacuum heat insulating container 104 in this way, the mud collection container 113 and the concentration tank 115 can be disposed substantially parallel to the vacuum heat insulating container 104, so that the disk-type magnetic filter 103 is replaced with a superconducting magnet. Compared with the case where it is arranged below 105, since the height of the concentration tank 115 can be increased without increasing the height of the entire apparatus, the sludge concentration can be further increased. The supernatant water from which the particles have settled and separated can be taken out from the overflow outlet 117 of the concentrating tank 115, and the amount of flow from the mud collection container 113 to the concentrating tank 115 is adjusted from the overflow adjusting valve 118 and the sludge extraction port 116. Adjustment is possible by adjusting the pull-out amount. In this case, the amount of flow from the mud collecting container 113 to the concentrating tank 115 is the amount of discharge adjusted by the flow rate adjusting valve 124 provided in the middle of the discharge piping of the water injection pump 125 and the amount of extraction from the sludge extraction port 116. Almost determined by adjustment. The supernatant water of the sludge concentration tank 115 is returned from the pipe 117 to the raw water tank (not shown in the figure) through the flow rate adjustment valve 118. A check valve 119 is installed on the upstream side of the sprinkling pipe 111 to prevent backflow. Further, the inclination angle of the side wall of the mud collection container 113 is larger than the repose angle of the particles that settle, so that the particle group does not accumulate in the mud collection container 113 but sinks into the concentration tank 115. In addition, the thickening tank 115 can take the sludge concentrated by gravity from the sludge extraction port 116 by taking an angle larger than the repose angle of the concentrated particles. The rotary filter 103 is stored in a fixed filter case 120, and watertightness to the outside is maintained by a partition wall. The rotary filter 103 can be rotated continuously or intermittently by the driving force of the electric motor 109 that can change the speed around the central shaft 102, and the portion where the central shaft 102 penetrates the filter case 120 has a structure that does not leak water by the shaft sealing mechanism. Yes. The electric motor 109 may be disposed at a distance from the superconducting magnet 105, and the magnetic filter may be driven via a chain, a belt, a shaft, or the like. The vacuum insulation container is provided with an inlet 122 for injecting liquid helium via a gate valve 121 and a helium gas safety valve 123. When the superconducting magnet 105 is quenched, the helium gas is connected to the safety valve 123. It is discharged to a safe place through the conduit. The arrangement order of the sprinkling amount adjusting valve 124 and the check valve 119 is not adversely affected even if it is reverse to the present embodiment. According to the present embodiment, not only the structure of the magnetic separation device is simplified, but also the amount of magnetic powder injection can be greatly reduced by the filter structure capable of maintaining a high magnetic field and a high gradient magnetic field, and further, washing Since the peeled magnetic aggregates are reduced in volume by concentration, post-treatment facilities such as magnetic powder recovery processing and sludge dehydration can be reduced in size, so that initial costs and running costs can be reduced.
[0042]
FIG. 7 is a flowchart of the embodiment of the magnetic separation system including FIG. 5 and FIG. 6 and magnetic powder recovery and reuse. Roughly speaking, water intake means, water supply means, additive injection means, floc forming means, magnetic separation means, purification It consists of water discharge means, magnetic powder recovery and reuse means, and sludge dewatering means. The raw water containing pollutants such as phosphate and blue seawater is taken from the lake and the like by the water intake means and sent to the magnetic separation means by the water supply means. In the water supply path to the magnetic separation means, the additive injection means injects an additive necessary for generating the magnetic aggregate, and the floc forming means generates the magnetic aggregate that is an aggregate of magnetic powder and contaminants. . When the pollutant is soluble inorganic phosphoric acid, it chemically reacts with the agglomeration additive to produce an insoluble metal salt, and aggregates are produced. In the magnetic separation means, the magnetic aggregates are separated and concentrated from the water to be treated containing the magnetic aggregates, and the purified water is recycled or reused as purified water by the purified water discharge means. The concentrated magnetic agglomerates are separated into magnetic powder and contaminated sludge by magnetic powder recovery and reuse means, and the magnetic powder is reused. Sludge is dewatered by sludge dewatering means to become dewatered sludge.
[0043]
The water intake means is composed of a screen 128, a water intake tank 129, a water intake pump 130, etc., and raw water 131 containing contaminants such as phosphates and solid suspended solids passes through the screen 128 and flows down to the water intake tank 129. Water is taken in by a water intake pump 130 installed in the water tank 129 and sent to the raw water tank 132. On the screen 128, coarse dust floating in the raw water is removed in advance, and the removed dust is discarded. The intake pump 130 is a submersible pump and is controlled in conjunction with water level meters provided in the intake tank 129 and the raw water tank 132, respectively. Reference numeral 133 denotes a water supply pipe, which is connected to the raw water tank 132 from the discharge port of the water intake pump 130, and a gate valve and a check valve are connected therebetween.
[0044]
The water supply means includes a raw water tank 132, a raw water stirrer 134, a water supply pump 136, a water supply pipe 136, and the like. The raw water tank 132 supplies the raw water taken by the water intake means and the supernatant water and sludge dewatered in the concentration tank 115 described in FIG. Water to be treated such as separated water of the means flows in, and the raw water agitator 134 makes it possible to make the concentration of contaminants uniform and to prevent sedimentation of contaminants. The water to be treated is drawn from the raw water tank 132 by the water pump 135 connected to the raw water tank 132 by a conduit, passes through the water supply pipe 136 connected to the discharge port of the water pump 135, and passes through the additive injection means and the flock forming means. Sent to the magnetic separation means. A flow rate adjustment valve 137, a check valve 138, a flow meter 139, a turbidity meter 140, and a pressure gauge 141 are connected to the water supply pipe 136. Further, the water supply pipe is branched in the middle, and a part of the water to be treated is returned to the raw water tank 132 to adjust the amount of water supply and to stir the raw water tank 132. The treated water is returned to the raw water tank 132 through the return pipe 143. A check valve is provided in the middle of the return pipe to prevent backflow. The water pump 135 is interlocked with a water level meter provided in the raw water tank 132, and when the water level of the raw water tank 132 is abnormally lowered, the water pump 135 is stopped to prevent an accident such as a failure of the water pump 135.
[0045]
The additive injection means includes magnetic powder injection means, inorganic flocculant injection means, pH adjuster injection means, and polymer flocculant injection means. The magnetic powder injection means includes a magnetic powder hopper 144, a magnetic powder feeder 145, a diluted water injection pipe 146, and a magnetic powder slurry agitator 147. The magnetic powder is stored in the magnetic powder hopper 144, and the magnetic powder hopper 144 A magnetic powder feeder 145 provided at the bottom of the hopper 144 is put into the magnetic powder dilution tank 148. The diluted water is injected from the purified water tank 149 through the diluted water injection pipe 146 by the purified water pump 150 into the magnetic powder dilution tank 148 and mixed with the magnetic powder by the magnetic powder slurry agitator 147 provided in the magnetic powder dilution tank 148. Thus, the magnetic powder slurry is replenished. The magnetic powder hopper 144 is connected to a magnetic powder input port 151 and a recovered magnetic powder input means 152 so that the magnetic powder is replenished. The magnetic powder feeder 145 is linked to a water level meter and an input amount integrating meter 153 provided in the magnetic powder dilution tank 148. When the liquid level of the magnetic powder dilution tank 148 is lowered to a predetermined position, the operation is started and the input amount is integrated. The operation is stopped when a predetermined amount is accumulated in total 153. An integrating flow meter 145 and an electromagnetic valve 155 are connected to the dilution water injection pipe 146, and the electromagnetic valve 155 is linked to the water level meter and the integrating flow meter 154 of the magnetic powder dilution tank 148, and the liquid level of the magnetic powder dilution tank 148. When the water level drops to a predetermined position, it opens and water injection starts, and when a predetermined flow rate is integrated by the integrated flow meter 154, it closes and water injection stops. In addition, the magnetic powder slurry injection pump 156 is linked to the water level gauge of the magnetic powder dilution tank 148, and stops when the liquid level of the magnetic powder dilution tank 148 is abnormally lowered, causing an accident such as failure of the magnetic powder slurry injection pump 156. Is prevented in advance. Although not shown, the magnetic powder hopper 144 is provided with an arch breaker to send dry air. As the magnetic powder feeder 145, a screw feeder or a table feeder is used.
[0046]
The inorganic flocculant injection means is means for injecting the inorganic flocculant stored in the inorganic flocculant storage tank 157 into the water supply pipe 136 through the inorganic flocculant injection pump 158 and the inorganic flocculant injection pipe 159. The inorganic flocculant storage tank 157 is provided with an inorganic flocculant stirrer 160, so that the inorganic flocculant concentration in the inorganic flocculant storage tank 157 is made uniform and deposition is prevented. The inorganic flocculant injection pump 158 is a positive displacement metering pump, interlocked with a water level meter provided in the inorganic flocculant storage tank 157, and stops when the liquid level of the inorganic flocculant storage tank 157 is abnormally lowered. Accidents such as failure of the flocculant injection pump 157 are prevented in advance. Further, an inorganic flocculant injection amount adjusting function is added to the magnetic powder injection amount control means and connected to the inorganic flocculant injection pump 158 to control the inorganic flocculant injection amount in accordance with the amount of contaminants in the water to be treated. Is also possible. As the inorganic flocculant, vane sulfate earth or iron-based inorganic flocculant is used, and the inorganic flocculant storage tank 157 is replenished from the replenishment port 161. The inorganic flocculant injection pipe 159 is connected to the water supply pipe 136 via a check valve.
[0047]
The pH adjusting agent injection means is suitable for coagulating the pH of the water to be treated by injecting the pH adjusting agent stored in the pH adjusting agent storage tank 162 into the water supply pipe 136 with the pH adjusting agent injection pump 163 and the pH adjusting agent injection pipe 164. It is means to adjust to the value. The pH adjusting agent storage tank 162 is provided with a pH adjusting agent stirrer 165 to achieve uniform concentration of the pH adjusting agent in the pH adjusting agent storage tank 162 and prevention of deposition. The pH adjusting agent injection pump 162 is a positive displacement metering pump, interlocked with a water level meter provided in the pH adjusting agent storage tank 162, and stops when the liquid level in the pH adjusting agent storage tank 162 is abnormally lowered. Accidents such as failure of the adjusting agent injection pump 163 are prevented in advance. Further, the pH of the water to be treated can be controlled by controlling the discharge amount of the pH adjusting agent injection pump using a pH meter and a pH controller. A sodium hydroxide solution or a calcium hydroxide solution is used as the pH adjusting agent, and the pH adjusting agent storage tank 162 is replenished from the replenishing port 166. The pH adjusting agent injection pipe 164 is connected to the water supply pipe 136 via a check valve.
[0048]
The polymer flocculant injection means includes a polymer flocculant hopper 167, an input accumulator 168, a polymer flocculant feeder 169, polymer flocculant dissolution tanks 170 and 171, polymer flocculant agitators 172 and 173, polymer flocculant It is composed of infusion pumps 174, 175 and the like. The polymer flocculant is stored in the polymer flocculant hopper 83, and the polymer flocculant dissolution tank 170 is fed from the polymer flocculant hopper 167 to the polymer flocculant feeder 169 provided below the polymer flocculant hopper 167. Alternatively, the diluted water is poured into the polymer flocculant dissolution tank 170 or 171 from the purified water tank 149 through the diluted water injection pipe 176 or 177 by the purified water pump 150. In the polymer flocculant dissolution tank 170 or 171, the polymer flocculant is dissolved in the dilution water by the polymer flocculant stirrer 172 or 173. Since dissolution of the polymer flocculant takes about 1 hour, dissolution and storage are alternately performed in the polymer flocculant dissolution tanks 170 and 171, and the capacity of each tank is set to be more than the capacity used for 1 hour. From the stored polymer flocculant dissolution tank, the water is injected into the water feed pipe 136 or the sludge dewatering means by the polymer flocculant injection pumps 174 and 175 and the polymer flocculant injection pipes 176 and 177. The polymer flocculant hopper 167 is replenished with the polymer flocculant from the polymer flocculant inlet 178. The polymer flocculant feeder 169 is interlocked with a water level meter provided in the polymer flocculant dissolution tank 170 or 171 and an input amount integrating meter 168, and the liquid level of the polymer flocculant dissolution tank 170 or 171 reaches a predetermined position. When it drops, the charging is started, and when a predetermined amount is integrated by the charging amount integrating meter 168, the charging is stopped. Further, the polymer flocculant feeder 169 has a mechanism for switching the charging destination, and can switch the charging destination to the polymer flocculant dissolution tank 170 or 171. Although not shown, the polymer flocculant hopper 167 is provided with an arch breaker to send dry air, and a screw feeder or a table feeder is used for the polymer flocculant hopper 167. An integrated flow meter 179 and an electromagnetic valve 225 are connected to the dilution water injection pipe. The electromagnetic valve 225 is linked to the water level meter and the integrated flow meter 179 of the polymer flocculant dissolution tank 170 or 171 to dissolve the polymer flocculant. When the liquid level in the tank 170 or 171 drops to a predetermined position, it opens and water injection is started, and when a predetermined flow rate is integrated by the integrated flow meter 179, it closes and water injection is stopped. Further, the dilution water injection pipe branches into a dilution water injection pipe 176 and a dilution water injection pipe 177, and is polymerized via an electromagnetic valve 180 or 181 that opens and closes in conjunction with the water level gauge of the polymer flocculant dissolution tank 170 or 171. Connected to the flocculant dissolution tank 170 or 171, the solenoid valve 180 or 181 is opened when the liquid level drops to a predetermined low water level and diluted water is injected, and when the liquid level rises to a predetermined high water level, it is closed and diluted. Water injection is stopped. The polymer flocculant injection pumps 174 and 175 are positive displacement metering pumps, interlocked with the water level gauge of the polymer flocculant dissolution tank 170 or 171, and the liquid level of the polymer flocculant dissolution tank 170 or 171 decreases abnormally. When this happens, it stops and accidents such as failure of the polymer flocculant injection pumps 174 and 175 are prevented. The suction ports of the polymer flocculant injection pumps 174 and 175 are connected in parallel to the polymer flocculant dissolution tanks 170 and 171, and the polymer flocculant dissolution tank in which storage is performed by switching the valves 182 and 183. And the polymer flocculant can be extracted. As the valves 182 and 183, electromagnetic valves, electric valves or the like are used, and opening / closing control is possible by interlocking with the water level gauges of the polymer flocculant dissolution tanks 170 and 171. A check valve is connected in the middle of the pipes of the polymer flocculant injection pipes 176 and 177 to prevent backflow.
[0049]
The floc forming means is composed of a rapid stirrer 184 and a slow stirrer 185 to which a water supply pipe 136 is connected, and a polymer flocculant injection pipe 176 is connected to a conduit connected to the quick stirrer 184 and the slow stirrer 185. A polymer flocculant is injected. The water to be treated into which the additive has been injected by the additive injection means is sent to the rapid stirrer through the water pipe 136, and the additive and contaminants (for example, solid suspended matters, phosphates, soluble heavy metals, E. coli, etc.) Are uniformly dispersed in the water to be treated to produce micro flocs, and then a polymer flocculant is injected into the water to be treated and magnetic aggregates are formed by a slow agitator. A static mixer with no moving parts is used for the rapid stirrer, and a sealed agitation tank and a stirrer with a predetermined capacity are used for the slow agitator. However, a static mixer or a pipe-type stirrer may be used for both. Is possible.
[0050]
The magnetic separation means is based on the magnetic separation apparatus described with reference to FIGS. 5 and 6, and the water to be treated containing magnetic aggregates is magnetically separated by a conduit 186 connected from the slow agitator 185 to the water conduit 110 of the magnetic separation unit. After being sent to the apparatus and magnetic agglomerates being magnetically separated, the purified water is sent to the purified water tank 149 through the conduit 187. Washing water used in the magnetic separation device is sent from the pressurizing pump 188 to the sprinkler pipe 111, and a check valve 119, a flow rate adjusting valve 124, and a flow meter 126 are provided in the wash water pipe. The supernatant water taken out from the concentration tank 115 of the magnetic separator is sent to the separation water tank 189 from the concentration tank upper supernatant water outlet by a conduit 190 connected to the separation water tank 189, and to the supernatant water outlet side of the conduit 190. Is provided with a flow meter 191 and a regulating valve 118 to adjust the amount of supernatant water taken out. The sludge concentrated and reduced in the concentration tank 115 is sent to the magnetic powder recovery and reuse means. Helium gas from the safety valve of the vacuum insulation container of the magnetic separation apparatus is discharged to the atmosphere from a safe discharge port 193 through a conduit 192 connected to the safety valve.
[0051]
Purified water is mainly used as cleaning water for the disk-type rotary filter 103 as well as diluting water for magnetic powder and coagulant, mainly by discharging the purified water obtained by the magnetic separation means to a lake or the like. Since part of the purified water is used as dilution water, it is once stored in the purified water tank 149 and discharged by the purified water pump 150 and the discharge pipe 194. The discharge pipe 194 is branched into the dilution water feed pipe 195 in the middle of the pipe, and a part of the purified water is used as the dilution water for the additive injection means. When the purified water tank 149 is empty or the amount of water is small, such as before the start of the purification operation, the cleaning water and dilution of the disk-type rotary filter 103 at the start of the operation are performed by replenishing the purified water tank 149 with a necessary amount of tap water. Water is secured. The tap water is connected to the tap water connection port 196 and injected into the purified water tank 149 through a valve. Regulating valves 197 and 198 are connected to the discharge pipe 194 and the dilution water transfer pipe 195, respectively, and the purified water distribution pressure from the discharge pipe 194 to the dilution water transfer pipe 195 can be adjusted. Prevention is intended. In addition, a pressure gauge 199 is provided in a pipe line between the purified water pump 150 and the diluting water transfer pipe 195 branch point, and the discharge pressure can be monitored. The purified water pump 150 is interlocked with a water level gauge provided in the purified water tank 149, and when the liquid level in the purified water tank 149 is abnormally lowered, the purified water pump 149 is stopped to prevent an accident such as a failure of the purified water pump 150. The In addition, when the purified water discharge destination is lower than the purified water tank 149 and the purified water pump 150 is not required for discharge, the purified water pump 150 is used only for diluting water supply, and the discharge from the purified water tank 149 is used. If the overflow is caused to flow down to the discharge destination through the conduit, the purified water pump 150 can be reduced in size, and if the purified water pump 150 is not required for diluting water supply, the purified water pump 150 is unnecessary and the device is It can be simplified. The washing water for the disk-type rotary filter 103 is also sent from the purified water tank by the washing water pressurizing pump. A cleaning flow meter 126, a flow rate adjustment valve 124, and a check valve 119 are arranged in the middle of the cleaning water pipe to prevent adjustment of the cleaning flow rate and backflow from the magnetic separation body.
[0052]
In the magnetic powder recovery and reuse means, the sludge of the magnetic aggregate drawn from the lower part of the concentration tank of the magnetic separation means is ground by the grinder 200 and decomposed with high purity into the sludge and the magnetic powder, and then the sludge pump 201, sludge The sludge sent to the magnetic separator 203 by the transfer pipe 202 and passed through the magnetic separator 203 flows down the conduit 204 and enters the sludge tank 205, and the magnetic powder recovered by the magnetic separator 203 passes through the recovered magnetic powder input means 152. The magnetic powder popper 144 is replenished and reused. A homomixer is used for the attritor 200, and a part of sludge can be continuously circulated by the conduit 206 bypassing the inlet and the outlet and the valve 207 in the conduit, so that the decomposition purity can be increased. Further, in this example, the sludge pump 201 is installed at the subsequent stage of the attritor 200, but the attritor 201 may be installed at the subsequent stage of the sludge pump 201. The amount of sludge sent from the concentration tank 115 to the magnetic separator 203 via the attritor 200 and the sludge pump 201 is adjusted by a valve provided on the sludge transfer pipe 202. The magnetic separator 203 includes a motor-driven rotating disk in which permanent magnets are embedded, a separation tank in which grinding sludge enters, and a scraper that scrapes off magnetic powder adsorbed by the permanent magnets of the disk, and a part of the rotating disk is a separation tank. The magnetic powder is adsorbed by the permanent magnet of the rotating disk until the sludge entered the separation tank rotates and flows into the overflow side on the opposite side and overflows. The powder moves into the air as the rotating disk rotates, and is scraped off and collected by a scraper. Further, stirring blades are provided on the outer periphery of the rotating disk and the inner wall of the separation tank, and sludge in the separation tank is agitated by the rotation of the rotating disk to prevent magnetic powder from being deposited. For example, a screw feeder or a belt conveyor can be used as the recovered magnetic powder input means 152. However, the magnetic separator 203 is disposed directly above the magnetic powder input port of the magnetic powder hopper 65, and the recovered magnetic powder is By dropping the magnetic powder into the magnetic powder hopper 144, the recovered magnetic powder input means 152 becomes unnecessary and the apparatus can be further simplified. Further, the magnetic separator 203 may be disposed just above the magnetic powder dilution tank 148 so that the recovered magnetic powder is dropped into the magnetic powder dilution tank 148 by gravity drop, and the recovered magnetic powder input means 152 is omitted. And the device can be simplified.
[0053]
The sludge dewatering means is a means for dewatering and reducing the volume of sludge by the sludge dewatering machine 208, and for making sludge transportation easy. The sludge is discharged from the sludge tank 205 by the sludge supply pump 209 and the supply pipe 210. To be supplied. The sludge dehydrator 208 is connected with a polymer flocculant injection pipe 177 from the additive injection means to inject the polymer flocculant, and the dewatered sludge is dropped into the shooter 211 from the sludge discharge port and is fed by the sludge feeder 212. The separated water is transferred to the sludge recovery container 213, and the separated water flows down from the separated water discharge port to the separated water tank 189 through the conduit 214 and is separated into the raw water tank 132 by the separated water pump 215 and the conduit 189 together with the supernatant water of the concentration tank of the magnetic separation means. Sent. The sludge supply pump 209 is a submersible slurry pump with a fritted switch. When the sludge liquid level in the sludge tank 205 is abnormally lowered, the sludge supply pump 209 is stopped to prevent an accident such as a failure of the sludge supply pump 209. Further, the separated water pump 215 is a submersible pump with a fritted switch, and stops when the water level of the separated water tank 209 is abnormally lowered to prevent an accident such as a failure of the separated water pump 215. A slurry flow meter 216 and a flow rate adjustment valve 217 are provided in the middle of the supply pipe 210. Further, a flow meter 218, a valve 219, and a check valve are connected in the middle of the conduit 216. The dewatered sludge 220 stored in the sludge collection container 213 can be transported and disposed of, for example, a waste disposal site, or can be recycled as a compost raw material. In particular, in facilities that do not collect and reuse magnetic iron powder, the iron content in the sludge increases, so that it can be recycled as a raw material for cement that requires iron.
[0054]
In addition, all the tanks used in the present embodiment are provided with a level gauge, an overflow pipe, and a drain pipe, and all the overflow and drain are collected in a drainage groove and drained into, for example, sewage. Moreover, it is also possible to use a tank made of reinforced concrete for the tanks used in this embodiment. Although the control panel is omitted in the figure, all the devices and devices constituting this embodiment are supplied with power from the control panel, and are operated and sequence controlled. Here, the power of this facility may use a normal commercial power source, and specially for this facility, power generation facilities such as wind power generation, solar power generation, biomass power generation, fuel cell power generation facilities are installed. These can be supplied alone or in combination. According to the present embodiment, space saving and energy saving are achieved by simplifying the operation of the operator at low cost by simplifying the structure of the magnetic separator, reducing the concentration of magnetic powder injection, and collecting and reusing the magnetic powder. -A magnetic separation device can be provided, and is suitable for purifying phosphorus and suspended solids in closed water areas such as lakes.
[0055]
Next, the vegetation equipment for removing nitrogen, which is the second purification step, is as follows. Two vegetation facilities for cultivating aquatic plants can be expected: water purification effects such as nitrogen removal by plants, and creation of ecosystems. The organic nitrogen in the treated water from which phosphorus and other substances have been separated and removed in the first purification process is decomposed by microorganisms adhering to the plant and converted to ammonia and inorganic salts such as nitrite and nitrate nitrogen. Is done. Since plants grow using solar energy while absorbing these inorganic salts, nitrogen components are taken into the plant body and removed from the water area. In addition, organisms attached to the surface of the plant also play an important role in decomposing organic substances and removing nutrients.
[0056]
Table 1 shows an example of measuring the removal rate of plants with respect to nitrogen and phosphorus as eutrophication substances in the water purification test of each plant.
[0057]
[Table 1]
Figure 0003939664
In the superconducting magnetic separation apparatus 5 used in the first purification process for removing phosphorus and the like, the installation space is that of an apparatus having a treated water volume of 5000 m 3 / day (corresponding to a water supply amount of about 20,000 people). In this case, the installation space is about 300m 2 Thus, a phosphorus removal rate of 85% or more can be obtained. On the other hand, when removing nitrogen in the vegetation purification facility 7 which is the second purification process, the vegetation area necessary for purifying the water volume of 5000 m3 / day is 10 ppm in the case of reeds. Approximately 500,000m 2 It is a calculation that can remove 67% of nitrogen in the reed field. This required area is an order of magnitude larger than that of the first phosphorus purification process.
[0058]
However, even if this vegetation area cannot be secured, the removal of one phosphorus of the eutrophic salt provides a more favorable environment for the growth of plants that were unable to grow and reproduce. And it becomes possible to grow using residual phosphorus as a nutrient source. This is because it has been found that algae such as blue-green algae can be prevented from breeding even if certain conditions such as nutrient salts, light, water temperature, carbon dioxide gas, and water circulation are lacking.
[0059]
Therefore, in reality, it is difficult to separate and remove nitrogen for the entire amount of treated water of the phosphorus removal device due to the limitation of the installation space of the vegetation 7, but about a part of the treated water of the superconducting magnetic separation device 5 Even if it is purified by vegetation 7, it is possible to achieve part of the purpose. For this reason, the second purification step may be bypassed for most of the treated water from which the contaminants have been separated and removed in the first purification step. The bird's-eye view of FIG. 1 shows such an example, the partition body 14 is disposed so as to surround the second water purification region 6b in which the second purification step is performed, and the second water purification region 6b in the second purification step. It is designed to allow the stored water to flow around the offshore side of the river.
[0060]
Here, there is no problem even if water is mixed in the first water purification area 6a of the bypass channel and the second water purification area 6b of the vegetation zone, and the water flow propagated through the purification area 6 partitioned from the lake 2 Or the partition 14 of the grade which can prevent a wave is enough. Moreover, in the purification area | region 6, it is sufficient if it can suppress to some extent that water mixes with the partition body 10 with the lake water outside it. Conversely, by allowing the partition body 10 to enter and leave a small amount of water, the external force applied to the partition body 10 due to the river flow or the blowing flow is alleviated, and the partition body 10 can be prevented from flowing out.
[0061]
In addition, for example, in the case of a tap water source, even if the amount of water intake at night is reduced, if the operation of the superconducting magnetic separation device 5 is continued, the amount of stored water in the purification region 6 increases, Out of the lake 2 and contribute to purification as dilution water of the lake. Furthermore, it is more effective to carry out not only purification of river water but also removal of dredged sediment from the lake. This is because the eutrophic lake is in an anoxic state near the bottom, and the accumulated phosphorus and nitrogen are eluted from the bottom mud and further added to the nutrient load.
[0062]
In addition, in the first purification step, a coagulation precipitation filtration method can be applied. This is because phosphate and suspended solids can be removed by this method.
[0063]
According to the present embodiment, a part of water flowing from a river or the like into a closed water area 2 such as a lake is taken, and this water is physicochemically processed to mainly remove phosphorus, The treated water treated in the first purification step is introduced into the purification region 6 formed by partitioning the closed water region 2 in the depth direction, and the treated water is biologically treated in the purification region 6 to mainly generate nitrogen. Since it consists of the 2nd purification process to remove, the eutrophication by the pollutants such as phosphorus and nitrogen in the purification area 6 such as lakes and marshes is suppressed, and a water source for high-quality water is obtained and the hydrophilicity of the purification area 6 And restore the original ecosystem.
[0064]
Furthermore, since the physicochemical treatment is performed using the superconducting magnetic separation device 5, high-speed and high-efficiency phosphorus separation / removal can be performed, thereby achieving a significant space saving and energy saving in water purification.
[0065]
Furthermore, since biological treatment using vegetation is performed, it is possible to restore the original ecosystem while improving the landscape of the purification region 6 constituting a specific portion in the closed region 2.
[0066]
In addition, a part of water flowing from a river or the like into a closed water area 2 such as a lake and the like, and a superconducting magnetic separation process to remove mainly phosphorus, and a closed water area 2 The treated water treated in the first purification step is diverted into the first purification region 6a and the second purification region 6b formed by partitioning the water in the depth direction and introduced into the second purification region 6b. Since the introduced treated water consists of a second purification step in which the treated water is biologically treated in the second purification region 6b to mainly remove nitrogen, the water quality improvement of the closed water area 6 having a relatively large amount of stored water is more effective. Can be carried out reliably.
[0067]
Further, since the first purification region 6a is provided so as to be adjacent to and surround the second purification region 6b, the treated water in the first and second purification regions 6a and 6b flows out and mixes. Even if this is the case, the treated water is mixed and the first purification region 6a is not contaminated, and the predetermined purification performance in the second purification region 6b can be ensured.
[0068]
【The invention's effect】
According to the present invention, a purification method for lakes and the like that can suppress eutrophication due to contaminants such as phosphorus and nitrogen in a purification region such as lakes and marshes while minimizing facility costs, installation space, and drive energy. And a purification system thereof.
[0069]
Moreover, according to this invention, the purification method and its purification system of lakes etc. which can perform the water quality improvement of the closed water area with comparatively big stored water amount more effectively and reliably can be obtained.
[Brief description of the drawings]
FIG. 1 is a plan view of a peripheral portion to which a purification system such as a lake is applied according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
3 is a cross-sectional view corresponding to AA in FIG. 1 of an application example different from FIG. 2;
4 is a side view showing a part of a partition body in the purification system of FIG. 1; FIG.
FIG. 5 is a configuration diagram of a magnetic separation unit of a superconducting magnetic separation device in the purification system of FIG. 1;
6 is a cross-sectional view showing a magnetic separation medium of the superconducting magnetic separation device of FIG.
7 is a flowchart showing a system configuration of a superconducting magnetic separation device in the purification system of FIG. 1; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Inflow river, 1a ... River water intake, 2 ... Closed water area (lake etc.), 3 ... Lake shore, 4 ... Outflow river, 4a ... Overflow cough, 5 ... Superconducting magnetic separation device (physicochemical processing equipment) ) 5a ... first treated water discharge port, 6 ... purification region, 6a ... first purification region, 6b ... second purification region, 7 ... vegetation, 8 ... first purification process water region, 9 ... water intake intake, DESCRIPTION OF SYMBOLS 10 ... 1st partition body, 11 ... Floating island, 12 ... Floating island float, 13 ... Floating island soil, 14 ... Second partition body, 15 ... Floating island anchor, 16 ... Floating island water level adjustment communication pipe, 20 ... Partition Plate, 21 ... chain, 22 ... weight, 23 ... floating member, 30 ... biological treatment equipment.

Claims (9)

湖沼などの閉鎖性水域に河川などから流入する水の一部を取水し、この水を物理化学的に処理して主にリンを除去する第一の浄化工程と、
前記閉鎖性水域を深さ方向に仕切って形成した浄化領域に前記第一の浄化工程で処理された処理水を導入し、この処理水を前記浄化領域内で生物処理して主に窒素を除去する第二の浄化工程とを有する
ことを特徴とする湖沼などの浄化方法。
A first purification step in which a part of water flowing from a river or the like is taken into a closed water area such as a lake, and this water is physicochemically processed to mainly remove phosphorus;
The treated water treated in the first purification step is introduced into a purification region formed by partitioning the closed water area in the depth direction, and the treated water is biologically treated in the purification region to mainly remove nitrogen. A purification method for lakes and marshes characterized by comprising a second purification step.
請求項1において、超電導式磁気分離装置を用いて前記物理化学的処理を行なうことを特徴とする湖沼などの浄化方法。The method for purifying lakes and marshes according to claim 1, wherein the physicochemical treatment is performed using a superconducting magnetic separator. 請求項1または2において、前記生物処理は植生を用いた生物処理であることを特徴とする湖沼などの浄化方法。The method for purifying lakes and marshes according to claim 1 or 2, wherein the biological treatment is biological treatment using vegetation. 湖沼などの閉鎖性水域に河川などから流入する水の一部を取水し、この水を超電導式磁気分離処理して主にリンを除去する第一の浄化工程と、
前記閉鎖性水域を深さ方向に仕切って形成した第一の浄化領域および第二の浄化領域に前記第一の浄化工程で処理された処理水を分流してそれぞれに導入し、前記第二の浄化領域に導入した処理水をその浄化領域内で生物処理して主に窒素を除去する第二の浄化工程とを有する
ことを特徴とする湖沼などの浄化方法。
A first purification step of taking a part of water flowing from a river into a closed water area such as a lake, and superconducting magnetic separation treatment to remove mainly phosphorus;
The treated water treated in the first purification step is diverted into the first purification region and the second purification region formed by partitioning the closed water region in the depth direction, and each is introduced to the second purification region. A purification method for lakes and marshes, etc., comprising a second purification step in which treated water introduced into the purification region is biologically treated in the purification region to mainly remove nitrogen.
請求項4において、前記第二の浄化領域に隣接してこれを取り囲むように前記第一の浄化領域を設けたことを特徴とする湖沼などの浄化方法。The method for purifying lakes and the like according to claim 4, wherein the first purification region is provided so as to be adjacent to and surround the second purification region. 湖沼などの閉鎖性水域に河川などから流入する水の一部を取水して主にリンを除去する物理化学的処理設備と、
前記閉鎖性水域を深さ方向に仕切って形成され且つ前記物理化学処理装置で処理された処理水を導入する浄化領域内に配置されて主に窒素を除去する生物処理設備とを備えた
ことを特徴とする湖沼などの浄化システム。
A physicochemical treatment facility that mainly removes phosphorus by taking a part of water flowing from rivers into closed water areas such as lakes,
A biological treatment facility that is formed by partitioning the closed water area in the depth direction and disposed in a purification area for introducing treated water treated by the physicochemical treatment apparatus, and mainly removing nitrogen. A purification system for lakes and other features.
請求項6において、前記物理化学的処理設備は超電導式磁気分離装置であることを特徴とする湖沼などの浄化システム。The purification system for lakes and marshes according to claim 6, wherein the physicochemical treatment facility is a superconducting magnetic separator. 請求項6において、前記生物処理設備は植生を用いた生物処理設備であることを特徴とする湖沼などの浄化システム。The purification system for lakes and marshes according to claim 6, wherein the biological treatment facility is a biological treatment facility using vegetation. 湖沼などの閉鎖性水域に河川などから流入する水の一部を取水して主にリンを除去する超電導式磁気分離装置と、
閉鎖性水域を深さ方向に仕切って形成され且つ前記超電導式磁気分離装置で処理された処理水を分流してそれぞれに導入される複数の浄化領域の一方の浄化領域に配置されて主に窒素を除去する生物処理設備とを備えた
ことを特徴とする湖沼などの浄化システム。
A superconducting magnetic separation device that mainly removes phosphorus by taking a part of water flowing from rivers into closed water areas such as lakes,
Nitrogen is mainly disposed in one purification region of a plurality of purification regions formed by partitioning a closed water region in the depth direction and diverting the treated water treated by the superconducting magnetic separation device and introducing each of the treated water. A purification system for lakes and marshes characterized by a biological treatment facility that removes water.
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